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Zhao F, Shao M, Li M, Li T, Zheng Y, Sun W, Ni C, Li L. Sphingolipid metabolites involved in the pathogenesis of atherosclerosis: perspectives on sphingolipids in atherosclerosis. Cell Mol Biol Lett 2025; 30:18. [PMID: 39920588 PMCID: PMC11804087 DOI: 10.1186/s11658-024-00679-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2024] [Accepted: 12/17/2024] [Indexed: 02/09/2025] Open
Abstract
Atherosclerosis, with its complex pathogenesis, is a leading underlying cause of many cardiovascular diseases, which are increasingly prevalent in the population. Sphingolipids play an important role in the development of atherosclerosis. Key metabolites and enzymes in sphingolipid metabolism influence the pathogenesis of atherosclerosis in a variety of ways, including inflammatory responses and oxidative stress. Thus, an investigation of sphingolipid metabolism-related metabolites and key enzymes may provide novel insights and treatment targets for atherosclerosis. This review discusses various mechanisms and research progress on the relationship between various sphingolipid metabolites, related enzymes, and atherosclerosis. Finally, we look into the future research direction of phytosphingolipids.
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Affiliation(s)
- Fufangyu Zhao
- National Institute of Traditional Chinese Medicine Constitution and Preventive Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 102488, China
| | - Mingyan Shao
- National Institute of Traditional Chinese Medicine Constitution and Preventive Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Mingrui Li
- National Institute of Traditional Chinese Medicine Constitution and Preventive Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Tianxing Li
- National Institute of Traditional Chinese Medicine Constitution and Preventive Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Yanfei Zheng
- National Institute of Traditional Chinese Medicine Constitution and Preventive Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China.
| | - Wenlong Sun
- Institute of Biomedical Research, School of Life Sciences, Shandong University of Technology, Zibo, 255000, Shandong, China.
| | - Cheng Ni
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 102488, China.
| | - Lingru Li
- National Institute of Traditional Chinese Medicine Constitution and Preventive Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China.
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Kuo A, Hla T. Regulation of cellular and systemic sphingolipid homeostasis. Nat Rev Mol Cell Biol 2024; 25:802-821. [PMID: 38890457 PMCID: PMC12034107 DOI: 10.1038/s41580-024-00742-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2024] [Indexed: 06/20/2024]
Abstract
One hundred and fifty years ago, Johann Thudichum described sphingolipids as unusual "Sphinx-like" lipids from the brain. Today, we know that thousands of sphingolipid molecules mediate many essential functions in embryonic development and normal physiology. In addition, sphingolipid metabolism and signalling pathways are dysregulated in a wide range of pathologies, and therapeutic agents that target sphingolipids are now used to treat several human diseases. However, our understanding of sphingolipid regulation at cellular and organismal levels and their functions in developmental, physiological and pathological settings is rudimentary. In this Review, we discuss recent advances in sphingolipid pathways in different organelles, how secreted sphingolipid mediators modulate physiology and disease, progress in sphingolipid-targeted therapeutic and diagnostic research, and the trans-cellular sphingolipid metabolic networks between microbiota and mammals. Advances in sphingolipid biology have led to a deeper understanding of mammalian physiology and may lead to progress in the management of many diseases.
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Affiliation(s)
- Andrew Kuo
- Vascular Biology Program, Boston Children's Hospital, Department of Surgery, Harvard Medical School, Boston, MA, USA
| | - Timothy Hla
- Vascular Biology Program, Boston Children's Hospital, Department of Surgery, Harvard Medical School, Boston, MA, USA.
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SenthilKumar G, Zirgibel Z, Cohen KE, Katunaric B, Jobe AM, Shult CG, Limpert RH, Freed JK. Ying and Yang of Ceramide in the Vascular Endothelium. Arterioscler Thromb Vasc Biol 2024; 44:1725-1736. [PMID: 38899471 PMCID: PMC11269027 DOI: 10.1161/atvbaha.124.321158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Ceramides, a group of biologically active sphingolipids, have been described as the new cholesterol given strong evidence linking high plasma ceramide with endothelial damage, risk for early adverse cardiovascular events, and development of cardiometabolic disease. This relationship has sparked great interest in investigating therapeutic targets with the goal of suppressing ceramide formation. However, the growing data challenge this paradigm of ceramide as solely eliciting detrimental effects to the cardiovascular system. Studies show that ceramides are necessary for maintaining proper endothelial redox states, mechanosensation, and membrane integrity. Recent work in preclinical models and isolated human microvessels highlights that the loss of ceramide formation can in fact propagate vascular endothelial dysfunction. Here, we delve into these conflicting findings to evaluate how ceramide may be capable of exerting both beneficial and damaging effects within the vascular endothelium. We propose a unifying theory that while basal levels of ceramide in response to physiological stimuli are required for the production of vasoprotective metabolites such as S1P (sphingosine-1-phosphate), the chronic accumulation of ceramide can promote activation of pro-oxidative stress pathways in endothelial cells. Clinically, the evidence discussed here highlights the potential challenges associated with therapeutic suppression of ceramide formation as a means of reducing cardiovascular disease risk.
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Affiliation(s)
- Gopika SenthilKumar
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee WI
- Department of Physiology, Medical College of Wisconsin, Milwaukee WI
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee WI
| | - Zachary Zirgibel
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee WI
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee WI
| | - Katie E. Cohen
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee WI
- Division of Cardiovascular Medicine, Department of Medicine, Medical College of Wisconsin, Milwaukee WI
| | - Boran Katunaric
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee WI
- Department of Physiology, Medical College of Wisconsin, Milwaukee WI
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee WI
| | - Alyssa M. Jobe
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee WI
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee WI
| | - Carolyn G. Shult
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee WI
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee WI
| | - Rachel H. Limpert
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee WI
- Department of Physiology, Medical College of Wisconsin, Milwaukee WI
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee WI
| | - Julie K. Freed
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee WI
- Department of Physiology, Medical College of Wisconsin, Milwaukee WI
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee WI
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SenthilKumar G, Katunaric B, Zirgibel Z, Lindemer B, Jaramillo-Torres MJ, Bordas-Murphy H, Schulz ME, Pearson PJ, Freed JK. Necessary Role of Ceramides in the Human Microvascular Endothelium During Health and Disease. Circ Res 2024; 134:81-96. [PMID: 38037825 PMCID: PMC10766100 DOI: 10.1161/circresaha.123.323445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 12/02/2023]
Abstract
BACKGROUND Elevated plasma ceramides and microvascular dysfunction both independently predict adverse cardiac events. Despite the known detrimental effects of ceramide on the microvasculature, evidence suggests that activation of the shear-sensitive, ceramide-forming enzyme NSmase (neutral sphingomyelinase) elicits formation of vasoprotective nitric oxide (NO). Here, we explore a novel hypothesis that acute ceramide formation through NSmase is necessary for maintaining NO signaling within the human microvascular endothelium. We further define the mechanism through which ceramide exerts beneficial effects and discern key mechanistic differences between arterioles from otherwise healthy adults (non-coronary artery disease [CAD]) and patients diagnosed with CAD. METHODS Human arterioles were dissected from discarded surgical adipose tissue (n=166), and vascular reactivity to flow and C2-ceramide was assessed. Shear-induced NO and mitochondrial hydrogen peroxide (H2O2) production were measured in arterioles using fluorescence microscopy. H2O2 fluorescence was assessed in isolated human umbilical vein endothelial cells. RESULTS Inhibition of NSmase in arterioles from otherwise healthy adults induced a switch from NO to NOX-2 (NADPH-oxidase 2)-dependent H2O2-mediated flow-induced dilation. Endothelial dysfunction was prevented by treatment with sphingosine-1-phosphate (S1P) and partially prevented by C2-ceramide and an agonist of S1P-receptor 1 (S1PR1); the inhibition of the S1P/S1PR1 signaling axis induced endothelial dysfunction via NOX-2. Ceramide increased NO production in arterioles from non-CAD adults, an effect that was diminished with inhibition of S1P/S1PR1/S1P-receptor 3 signaling. In arterioles from patients with CAD, inhibition of NSmase impaired the overall ability to induce mitochondrial H2O2 production and subsequently dilate to flow, an effect not restored with exogenous S1P. Acute ceramide administration to arterioles from patients with CAD promoted H2O2 as opposed to NO production, an effect dependent on S1P-receptor 3 signaling. CONCLUSION These data suggest that despite differential downstream signaling between health and disease, NSmase-mediated ceramide formation is necessary for proper functioning of the human microvascular endothelium. Therapeutic strategies that aim to significantly lower ceramide formation may prove detrimental to the microvasculature.
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Affiliation(s)
- Gopika SenthilKumar
- Department of Physiology (G.S., J.K.F.), Medical College of Wisconsin, Milwaukee, WI
- Cardiovascular Center (G.S., Z.Z., B.L., M.J.J.-T., H.B.-M., M.E.S., J.K.F.), Medical College of Wisconsin, Milwaukee, WI
- Department of Anesthesiology (G.S., B.K., Z.Z., B.L., M.J.J.-T., H.B.-M., M.E.S., J.K.F.), Medical College of Wisconsin, Milwaukee, WI
| | - Boran Katunaric
- Department of Anesthesiology (G.S., B.K., Z.Z., B.L., M.J.J.-T., H.B.-M., M.E.S., J.K.F.), Medical College of Wisconsin, Milwaukee, WI
| | - Zachary Zirgibel
- Cardiovascular Center (G.S., Z.Z., B.L., M.J.J.-T., H.B.-M., M.E.S., J.K.F.), Medical College of Wisconsin, Milwaukee, WI
- Department of Anesthesiology (G.S., B.K., Z.Z., B.L., M.J.J.-T., H.B.-M., M.E.S., J.K.F.), Medical College of Wisconsin, Milwaukee, WI
| | - Brian Lindemer
- Cardiovascular Center (G.S., Z.Z., B.L., M.J.J.-T., H.B.-M., M.E.S., J.K.F.), Medical College of Wisconsin, Milwaukee, WI
- Department of Anesthesiology (G.S., B.K., Z.Z., B.L., M.J.J.-T., H.B.-M., M.E.S., J.K.F.), Medical College of Wisconsin, Milwaukee, WI
| | - Maria J. Jaramillo-Torres
- Cardiovascular Center (G.S., Z.Z., B.L., M.J.J.-T., H.B.-M., M.E.S., J.K.F.), Medical College of Wisconsin, Milwaukee, WI
- Department of Anesthesiology (G.S., B.K., Z.Z., B.L., M.J.J.-T., H.B.-M., M.E.S., J.K.F.), Medical College of Wisconsin, Milwaukee, WI
| | - Henry Bordas-Murphy
- Cardiovascular Center (G.S., Z.Z., B.L., M.J.J.-T., H.B.-M., M.E.S., J.K.F.), Medical College of Wisconsin, Milwaukee, WI
- Department of Anesthesiology (G.S., B.K., Z.Z., B.L., M.J.J.-T., H.B.-M., M.E.S., J.K.F.), Medical College of Wisconsin, Milwaukee, WI
| | - Mary E. Schulz
- Cardiovascular Center (G.S., Z.Z., B.L., M.J.J.-T., H.B.-M., M.E.S., J.K.F.), Medical College of Wisconsin, Milwaukee, WI
- Department of Anesthesiology (G.S., B.K., Z.Z., B.L., M.J.J.-T., H.B.-M., M.E.S., J.K.F.), Medical College of Wisconsin, Milwaukee, WI
| | - Paul J. Pearson
- Department of Surgery, Division of Cardiothoracic Surgery (P.J.P.), Medical College of Wisconsin, Milwaukee, WI
| | - Julie K. Freed
- Department of Physiology (G.S., J.K.F.), Medical College of Wisconsin, Milwaukee, WI
- Cardiovascular Center (G.S., Z.Z., B.L., M.J.J.-T., H.B.-M., M.E.S., J.K.F.), Medical College of Wisconsin, Milwaukee, WI
- Department of Anesthesiology (G.S., B.K., Z.Z., B.L., M.J.J.-T., H.B.-M., M.E.S., J.K.F.), Medical College of Wisconsin, Milwaukee, WI
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SenthilKumar G, Katunaric B, Zirgibel Z, Lindemer B, Jaramillo-Torres MJ, Bordas-Murphy H, Schulz ME, Pearson PJ, Freed JK. Necessary Role of Acute Ceramide Formation in The Human Microvascular Endothelium During Health and Disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.02.543341. [PMID: 37333082 PMCID: PMC10274701 DOI: 10.1101/2023.06.02.543341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Background Elevated plasma ceramides independently predict adverse cardiac events and we have previously shown that exposure to exogenous ceramide induces microvascular endothelial dysfunction in arterioles from otherwise healthy adults (0-1 risk factors for heart disease). However, evidence also suggests that activation of the shear-sensitive, ceramide forming enzyme neutral sphingomyelinase (NSmase) enhances vasoprotective nitric oxide (NO) production. Here we explore a novel hypothesis that acute ceramide formation through NSmase is necessary for maintaining NO signaling within the human microvascular endothelium. We further define the mechanism through which ceramide exerts beneficial effects and discern key mechanistic differences between arterioles from otherwise healthy adults and patients with coronary artery disease (CAD). Methods Human arterioles were dissected from otherwise discarded surgical adipose tissue (n=123), and vascular reactivity to flow and C2-ceramide was assessed. Shear-induced NO production was measured in arterioles using fluorescence microscopy. Hydrogen peroxide (H2O2) fluorescence was assessed in isolated human umbilical vein endothelial cells. Results Inhibition of NSmase in arterioles from otherwise healthy adults induced a switch from NO to H2O2-mediated flow-induced dilation within 30 minutes. In endothelial cells, NSmase inhibition acutely increased H2O2 production. Endothelial dysfunction in both models was prevented by treatment with C2-ceramide, S1P, and an agonist of S1P-receptor 1 (S1PR1), while the inhibition of S1P/S1PR1 signaling axis induced endothelial dysfunction. Ceramide increased NO production in arterioles from healthy adults, an effect that was diminished with inhibition of S1P/S1PR1/S1PR3 signaling. In arterioles from patients with CAD, inhibition of NSmase impaired dilation to flow. This effect was not restored with exogenous S1P. Although, inhibition of S1P/S1PR3 signaling impaired normal dilation to flow. Acute ceramide administration to arterioles from patients with CAD also promoted H2O2 as opposed to NO production, an effect dependent on S1PR3 signaling. Conclusion These data suggest that despite key differences in downstream signaling between health and disease, acute NSmase-mediated ceramide formation and its subsequent conversion to S1P is necessary for proper functioning of the human microvascular endothelium. As such, therapeutic strategies that aim to significantly lower ceramide formation may prove detrimental to the microvasculature.
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Affiliation(s)
- Gopika SenthilKumar
- Department of Physiology, Medical College of Wisconsin
- Cardiovasular Center, Medical College of Wisconsin
- Department of Anesthesiology, Medical College of Wisconsin
| | | | - Zachary Zirgibel
- Cardiovasular Center, Medical College of Wisconsin
- Department of Anesthesiology, Medical College of Wisconsin
| | - Brian Lindemer
- Cardiovasular Center, Medical College of Wisconsin
- Department of Anesthesiology, Medical College of Wisconsin
| | - Maria J. Jaramillo-Torres
- Cardiovasular Center, Medical College of Wisconsin
- Department of Anesthesiology, Medical College of Wisconsin
| | - Henry Bordas-Murphy
- Cardiovasular Center, Medical College of Wisconsin
- Department of Anesthesiology, Medical College of Wisconsin
| | - Mary E. Schulz
- Cardiovasular Center, Medical College of Wisconsin
- Department of Anesthesiology, Medical College of Wisconsin
| | - Paul J. Pearson
- Department of Surgery, Division of Cardiothoracic Surgery, Medical College of Wisconsin
| | - Julie K. Freed
- Department of Physiology, Medical College of Wisconsin
- Cardiovasular Center, Medical College of Wisconsin
- Department of Anesthesiology, Medical College of Wisconsin
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Ashby JW, Mack JJ. Endothelial Control of Cerebral Blood Flow. THE AMERICAN JOURNAL OF PATHOLOGY 2021; 191:1906-1916. [PMID: 33713686 DOI: 10.1016/j.ajpath.2021.02.023] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/09/2021] [Accepted: 02/24/2021] [Indexed: 12/19/2022]
Abstract
Since constant perfusion of blood throughout the brain is critical for neuronal health, the regulation of cerebral blood flow is complex and highly controlled. This regulation is controlled, in part, by the cerebral endothelium. In this review, multiple modes of endothelium-derived blood flow regulation is discussed, including chemical control of vascular tone, heterotypic and homotypic cell-cell interactions, second messenger signaling, and cellular response to physical forces and inflammatory mediators. Because cerebral small vessel disease is often associated with endothelial dysfunction and a compromised blood-brain barrier, understanding the endothelial factors that regulate vessel function to maintain cerebral blood flow and prevent vascular permeability may provide insights into disease prevention and treatment.
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Affiliation(s)
- Julianne W Ashby
- Division of Cardiology, Department of Medicine, University of California, Los Angeles, California
| | - Julia J Mack
- Division of Cardiology, Department of Medicine, University of California, Los Angeles, California.
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Yildirim C, Özkaya B, Bal R. KATP and TRPM2-like channels couple metabolic status to resting membrane potential of octopus neurons in the mouse ventral cochlear nucleus. Brain Res Bull 2021; 170:115-128. [PMID: 33581312 DOI: 10.1016/j.brainresbull.2021.02.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 02/04/2021] [Accepted: 02/06/2021] [Indexed: 12/29/2022]
Abstract
ATP-sensitive potassium (KATP) channels and transient receptor potential melastatin 2 (TRPM2) channels are commonly expressed both pre- and postsynaptically in the central nervous system (CNS). We hypothesized that KATP and TRPM2 may couple metabolic status to the resting membrane potential of octopus neurons of the mouse ventral cochlear nucleus (VCN). Therefore, we studied the expression of KATP channels and TRPM2 channels in octopus cells by immunohistochemical techniques and their contribution to neuronal electrical properties by the electrophysiological patch clamp technique. In immunohistochemical staining of octopus cells, labelling with Kir6.2 and SUR1 antibodies was strong, and labelling with the SUR2 antibody was moderate, but labelling with Kir6.1 was very weak. Octopus cells had intense staining with TRPM2 antibodies. In patch clamp recordings, bath application of KATP channel agonists H2O2 (880 μM), ATZ (1 mM), cromakalim (50 μM), diazoxide (200 μM), NNC 55-0118 and NN 414 separately resulted in hyperpolarizations of resting potential to different extents. Application of 8-Bro-cADPR (50 μM), a specific antagonist of TRPM2 channels, in the presence of H2O2 (880 μM) resulted in further hyperpolarization by approximately 1 mV. The amplitudes of H2O2-induced outward KATP currents and ADPR-induced inward currents were 206.1 ± 31.5 pA (n = 4) and 136.8 ± 22.4 pA, respectively, at rest. Their respective reversal potentials were -77 ± 2.6 mV (n = 3) and -6.3 ± 2.9 (n = 3) and -6.3 ± 2.9 (n = 3). In conclusion, octopus cells appear to possess both KATP channels and TRPM2-like channels. KATP might largely be constituted by SUR1-Kir6.2 subunits and SUR2-Kir6.2 subunits. Both KATP and TRPM2-like channels might have a modulatory action in setting the membrane potential.
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Affiliation(s)
- Caner Yildirim
- Department of Physiology, Faculty of Medicine, Gaziantep University, 27310, Gaziantep, Turkey
| | - Beytullah Özkaya
- Department of Physiology, Faculty of Medicine, Gaziantep University, 27310, Gaziantep, Turkey
| | - Ramazan Bal
- Department of Physiology, Faculty of Medicine, Gaziantep University, 27310, Gaziantep, Turkey.
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Bommakanti N, Isbatan A, Bavishi A, Dharmavaram G, Chignalia AZ, Dull RO. Hypercapnic acidosis attenuates pressure-dependent increase in whole-lung filtration coefficient (K f). Pulm Circ 2017; 7:719-726. [PMID: 28727979 PMCID: PMC5841912 DOI: 10.1177/2045893217724414] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Hypercapnic acidosis (HCA) has beneficial effects in experimental models of lung injury by attenuating inflammation and decreasing pulmonary edema. However, HCA increases pulmonary vascular pressure that will increase fluid filtration and worsen edema development. To reconcile these disparate effects, we tested the hypothesis that HCA inhibits endothelial mechanotransduction and protects against pressure-dependent increases in the whole lung filtration coefficient (Kf). Isolated perfused rat lung preparation was used to measure whole lung filtration coefficient (Kf) at two levels of left atrial pressure (PLA = 7.5 versus 15 cm H2O) and at low tidal volume (LVt) versus standard tidal volume (STVt) ventilation. The ratio of Kf2/Kf1 was used as the index of whole lung permeability. Double occlusion pressure, pulmonary artery pressure, pulmonary capillary pressures, and zonal characteristics (ZC) were measured to assess effects of HCA on hemodynamics and their relationship to Kf2/Kf1. An increase in PLA2 from 7.5 to 15 cm H2O resulted in a 4.9-fold increase in Kf2/Kf1 during LVt and a 4.8-fold increase during STVt. During LVt, HCA reduced Kf2/Kf1 by 2.7-fold and reduced STVt Kf2/Kf1 by 5.2-fold. Analysis of pulmonary hemodynamics revealed no significant differences in filtration forces in response to HCA. HCA interferes with lung vascular mechanotransduction and prevents pressure-dependent increases in whole lung filtration coefficient. These results contribute to a further understanding of the lung protective effects of HCA.
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Affiliation(s)
- Nikhil Bommakanti
- 1 Department of Anesthesiology, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA.,2 Department of Bioengineering, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA
| | - Ayman Isbatan
- 1 Department of Anesthesiology, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA.,3 Lung Vascular Biology Laboratory, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA
| | - Avni Bavishi
- 1 Department of Anesthesiology, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA.,3 Lung Vascular Biology Laboratory, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA
| | - Gourisree Dharmavaram
- 1 Department of Anesthesiology, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA.,3 Lung Vascular Biology Laboratory, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA
| | - Andreia Z Chignalia
- 1 Department of Anesthesiology, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA.,3 Lung Vascular Biology Laboratory, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA
| | - Randal O Dull
- 1 Department of Anesthesiology, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA.,2 Department of Bioengineering, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA.,3 Lung Vascular Biology Laboratory, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA
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9
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Biwer LA, Taddeo EP, Kenwood BM, Hoehn KL, Straub AC, Isakson BE. Two functionally distinct pools of eNOS in endothelium are facilitated by myoendothelial junction lipid composition. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1861:671-9. [PMID: 27106139 PMCID: PMC4869716 DOI: 10.1016/j.bbalip.2016.04.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 03/10/2016] [Accepted: 04/16/2016] [Indexed: 12/21/2022]
Abstract
In resistance arteries, endothelial cells (EC) make contact with smooth muscle cells (SMC), forming myoendothelial junctions (MEJ). Endothelial nitric oxide synthase (eNOS) is present in the luminal side of the EC (apical EC) and the basal side of the EC (MEJ). To test if these eNOS pools acted in sync or separately, we co-cultured ECs and SMCs, then stimulated SMCs with phenylephrine (PE). Adrenergic activation causes inositol [1,4,5] triphosphate (IP3) to move from SMC to EC through gap junctions at the MEJ. PE increases MEJ eNOS phosphorylation (eNOS-P) at S1177, but not in EC. Conversely, we used bradykinin (BK) to increase EC calcium; this increased EC eNOS-P but did not affect MEJ eNOS-P. Inhibiting gap junctions abrogated the MEJ eNOS-P after PE, but had no effect on BK eNOS-P. Differential lipid composition between apical EC and MEJ may account for the compartmentalized eNOS-P response. Indeed, DAG and phosphatidylserine are both enriched in MEJ. These lipids are cofactors for PKC activity, which was significantly increased at the MEJ after PE. Because PKC activity also relies on endoplasmic reticulum (ER) calcium release, we used thapsigargin and xestospongin C, BAPTA, and PKC inhibitors, which caused significant decreases in MEJ eNOS-P after PE. Functionally, BK inhibited leukocyte adhesion and PE caused an increase in SMC cGMP. We hypothesize that local lipid composition of the MEJ primes PKC and eNOS-P for stimulation by PE, allowing for compartmentalized function of eNOS in the blood vessel wall.
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Affiliation(s)
- Lauren A Biwer
- Department of Molecular Physiology and Biophysics, University of Virginia, USA; Robert M. Berne Cardiovascular Research Center, University of Virginia, USA
| | - Evan P Taddeo
- Department of Pharmacology, University of Virginia, USA
| | | | - Kyle L Hoehn
- Department of Pharmacology, University of Virginia, USA; School of Biotechnology and Biomolecular Sciences, University of New South Wales, Australia
| | - Adam C Straub
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, USA; Heart, Lung, Blood and Vascular Medicine Institute; University of Pittsburgh, USA
| | - Brant E Isakson
- Department of Molecular Physiology and Biophysics, University of Virginia, USA; Robert M. Berne Cardiovascular Research Center, University of Virginia, USA.
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Transcriptional and Posttranslational Regulation of eNOS in the Endothelium. ADVANCES IN PHARMACOLOGY 2016; 77:29-64. [PMID: 27451094 DOI: 10.1016/bs.apha.2016.04.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nitric oxide (NO) is a highly reactive free radical gas and these unique properties have been adapted for a surprising number of biological roles. In neurons, NO functions as a neurotransmitter; in immune cells, NO contributes to host defense; and in endothelial cells, NO is a major regulator of blood vessel homeostasis. In the vasculature, NO is synthesized on demand by a specific enzyme, endothelial nitric oxide synthase (eNOS) that is uniquely expressed in the endothelial cells that form the interface between the circulating blood and the various tissues of the body. NO regulates endothelial and blood vessel function via two distinct pathways, the activation of soluble guanylate cyclase and cGMP-dependent signaling and the S-nitrosylation of proteins with reactive thiols (S-nitrosylation). The chemical properties of NO also serve to reduce oxidation and regulate mitochondrial function. Reduced synthesis and/or compromised biological activity of NO precede the development of cardiovascular disease and this has generated a high level of interest in the mechanisms controlling the synthesis and fate of NO in the endothelium. The amount of NO produced results from the expression level of eNOS, which is regulated at the transcriptional and posttranscriptional levels as well as the acute posttranslational regulation of eNOS. The goal of this chapter is to highlight and integrate past and current knowledge of the mechanisms regulating eNOS expression in the endothelium and the posttranslational mechanisms regulating eNOS activity in both health and disease.
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Jernigan PL, Makley AT, Hoehn RS, Edwards MJ, Pritts TA. The role of sphingolipids in endothelial barrier function. Biol Chem 2016; 396:681-91. [PMID: 25867999 DOI: 10.1515/hsz-2014-0305] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 04/08/2015] [Indexed: 12/31/2022]
Abstract
Sphingolipids are a ubiquitous family of essential lipids with an increasingly understood role as biologically active mediators in numerous physiologic and pathologic processes. Two particular sphingolipid species, sphingosine-1-phosphate and ceramide, and their metabolites interact both directly and indirectly with endothelial cells to regulate vascular permeability. Sphingosine-1-phosphate generally augments endothelial integrity while ceramide tends to promote vascular leak, and a tight balance between the two is necessary to maintain normal physiologic function. The mechanisms by which sphingolipids regulate endothelial barrier function are complex and occur through multiple different pathways, and disruptions or imbalances in these pathways have been implicated in a number of specific disease processes. With improved understanding of sphingolipid biology, endothelial function, and the interactions between the two, several targets for therapeutic intervention have emerged and there is immense potential for further advancement in this field.
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Shu X, Keller TCS, Begandt D, Butcher JT, Biwer L, Keller AS, Columbus L, Isakson BE. Endothelial nitric oxide synthase in the microcirculation. Cell Mol Life Sci 2015; 72:4561-75. [PMID: 26390975 PMCID: PMC4628887 DOI: 10.1007/s00018-015-2021-0] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 07/21/2015] [Accepted: 08/11/2015] [Indexed: 02/07/2023]
Abstract
Endothelial nitric oxide synthase (eNOS, NOS3) is responsible for producing nitric oxide (NO)--a key molecule that can directly (or indirectly) act as a vasodilator and anti-inflammatory mediator. In this review, we examine the structural effects of regulation of the eNOS enzyme, including post-translational modifications and subcellular localization. After production, NO diffuses to surrounding cells with a variety of effects. We focus on the physiological role of NO and NO-derived molecules, including microvascular effects on vessel tone and immune response. Regulation of eNOS and NO action is complicated; we address endogenous and exogenous mechanisms of NO regulation with a discussion of pharmacological agents used in clinical and laboratory settings and a proposed role for eNOS in circulating red blood cells.
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Affiliation(s)
- Xiaohong Shu
- College of Pharmacy, Dalian Medical University, Dalian, 116044, China
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, P.O. Box 801394, Charlottesville, VA, 22908, USA
| | - T C Stevenson Keller
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, P.O. Box 801394, Charlottesville, VA, 22908, USA
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, USA
| | - Daniela Begandt
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, P.O. Box 801394, Charlottesville, VA, 22908, USA
| | - Joshua T Butcher
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, P.O. Box 801394, Charlottesville, VA, 22908, USA
| | - Lauren Biwer
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, P.O. Box 801394, Charlottesville, VA, 22908, USA
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, USA
| | - Alexander S Keller
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, P.O. Box 801394, Charlottesville, VA, 22908, USA
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, USA
| | - Linda Columbus
- Department of Chemistry, University of Virginia, Charlottesville, USA
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, P.O. Box 801394, Charlottesville, VA, 22908, USA.
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, USA.
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Fenger M, Linneberg A, Jeppesen J. Network-based analysis of the sphingolipid metabolism in hypertension. Front Genet 2015; 6:84. [PMID: 25788903 PMCID: PMC4349157 DOI: 10.3389/fgene.2015.00084] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 02/17/2015] [Indexed: 01/11/2023] Open
Abstract
Common diseases like essential hypertension or diabetes mellitus are complex as they are polygenic in nature, such that each genetic variation only has a small influence on the disease. Genes operates in integrated networks providing the blue-print for all biological processes and conditional of the complex genotype determines the state and dynamics of any trait, which may be modified to various extent by non-genetic factors. Thus, diseases are heterogenous ensembles of conditions with a common endpoint. Numerous studies have been performed to define genes of importance for a trait or disease, but only a few genes with small effect have been identified. The major reasons for this modest progress is the unresolved heterogeneity of the regulation of blood pressure and the shortcomings of the prevailing monogenic approach to capture genetic effects in a polygenic condition. Here, a two-step procedure is presented in which physiological heterogeneity is disentangled and genetic effects are analyzed by variance decomposition of genetic interactions and by an information theoretical approach including 162 single nucleotide polymorphisms (SNP) in 84 genes in the sphingolipid metabolism and related networks in blood pressure regulation. As expected, almost no genetic main effects were detected. In contrast, two-gene interactions established the entire sphingolipid metabolic and related genetic network to be highly involved in the regulation of blood pressure. The pattern of interaction clearly revealed that epistasis does not necessarily reflects the topology of the metabolic pathways i.e., the flow of metabolites. Rather, the enzymes and proteins are integrated in complex cellular substructures where communication flows between the components of the networks, which may be composite in structure. The heritabilities for diastolic and systolic blood pressure were estimated to be 0.63 and 0.01, which may in fact be the maximum heritabilities of these traits. This procedure provide a platform for studying and capturing the genetic networks of any polygenic trait, condition, or disease.
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Affiliation(s)
- Mogens Fenger
- Department of Clinical Biochemistry, Copenhagen University Hospital Hvidovre, Denmark
| | | | - Jørgen Jeppesen
- Department of Cardiology, Glostrup University Hospital Glostrup, Denmark
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Mueller KE, Wolf K. C. pneumoniae disrupts eNOS trafficking and impairs NO production in human aortic endothelial cells. Cell Microbiol 2014; 17:119-30. [PMID: 25131610 DOI: 10.1111/cmi.12341] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 08/01/2014] [Accepted: 08/05/2014] [Indexed: 11/28/2022]
Abstract
Endothelial nitric oxide synthase (eNOS) generated NO plays a crucial physiological role in the regulation of vascular tone. eNOS is a constitutively expressed synthase whose enzymatic function is regulated by dual acylation, phosphorylation, protein-protein interaction and subcellular localization. In endothelial cells, the enzyme is primarily localized to the Golgi apparatus (GA) and the plasma membrane where it binds to caveolin-1. Upon stimulation, the enzyme is translocated from the plasma membrane to the cytoplasm where it generates NO. When activation of eNOS ceases, the majority of the enzyme is recycled back to the membrane fraction. An inability of eNOS to cycle between the cytosol and the membrane leads to impaired NO production and vascular dysfunction. Chlamydia pneumoniae is a Gram-negative obligate intracellular bacterium that primarily infects epithelial cells of the human respiratory tract, but unlike any other chlamydial species, C. pneumoniae displays tropism toward atherosclerotic tissues. In this study, we demonstrate that C. pneumoniae inclusions colocalize with eNOS, and the microorganism interferes with trafficking of the enzyme from the GA to the plasma membrane in primary human aortic endothelial cells. This mislocation of eNOS results in significant inhibition of NO release by C. pneumoniae-infected cells. Furthermore, we show that the distribution of eNOS in C. pneumoniae-infected cells is altered due to an intimate association of the Golgi complex with chlamydial inclusions rather than by direct interaction of the enzyme with the chlamydial inclusion membrane.
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Affiliation(s)
- Konrad E Mueller
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, 40536, USA
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15
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Wang TL. Statin (Mevalotin) preconditioning decreases infarct size in senile rat myocardial infarction model. J Acute Med 2014. [DOI: 10.1016/j.jacme.2014.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ramirez-Sanchez I, Aguilar H, Ceballos G, Villarreal F. (-)-Epicatechin-induced calcium independent eNOS activation: roles of HSP90 and AKT. Mol Cell Biochem 2012; 370:141-50. [PMID: 22865466 PMCID: PMC3812804 DOI: 10.1007/s11010-012-1405-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 07/25/2012] [Indexed: 10/28/2022]
Abstract
Cardiovascular disease (CVD) is a leading determinant of mortality and morbidity in the world. Epidemiologic studies suggest that flavonoid intake plays a role in the prevention of CVD. Consumption of cocoa products rich in flavonoids lowers blood pressure and improves endothelial function in healthy subjects as well as in subjects with vascular dysfunction such as smokers and diabetics. The vascular actions of cocoa follow the stimulation of nitric oxide (NO). These actions can be reproduced by the administration of the cocoa flavanol (-)-epicatechin (EPI). Previously, using human endothelial cells cultured in calcium-free media, we documented EPI effects on eNOS independently of its translocation from the plasmalemma. To further define the mechanisms behind EPI-eNOS activation in Ca(2+) -deprived endothelial cells, we evaluated the effects of EPI on the eNOS/AKT/HSP90 signaling pathway. Results document an EPI-induced phosphorylation/activation of eNOS, AKT, and HSP90. We also demonstrate that EPI induces a partial AKT/HSP90 migration from the cytoplasm to the caveolar membrane fraction. Immunoprecipitation assays of caveolar fractions demonstrate a physical association between HSP90, AKT, and eNOS. Thus, under Ca(2+)-free conditions, EPI stimulates NO synthesis via the formation of an active complex between eNOS, AKT, and HSP90.
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Affiliation(s)
- Israel Ramirez-Sanchez
- Department of Medicine, University of California, San Diego, San Diego, CA, USA. Escuela Superior de Medicina, Instituto Politecnico Nacional, Mexico, DF, Mexico
| | - Hugo Aguilar
- Department of Medicine, University of California, San Diego, San Diego, CA, USA
| | - Guillermo Ceballos
- Department of Medicine, University of California, San Diego, San Diego, CA, USA. Escuela Superior de Medicina, Instituto Politecnico Nacional, Mexico, DF, Mexico
| | - Francisco Villarreal
- Department of Medicine, University of California, San Diego, San Diego, CA, USA. UCSD Cardiology, 9500 Gilman Dr. 0613J, BSB 4028, La Jolla, CA 92093, USA
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17
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Shupik MA, Vanin AF, Alessenko AV. Interaction of the nitric oxide signaling system with the sphingomyelin cycle and peroxidation on transmission of toxic signal of tumor necrosis factor-α in ischemia-reperfusion. BIOCHEMISTRY (MOSCOW) 2012; 76:1197-209. [PMID: 22117546 DOI: 10.1134/s0006297911110010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
This review discusses the functional role of nitric oxide in ischemia-reperfusion injury and mechanisms of signal transduction of apoptosis, which accompanies ischemic damage to organs and tissues. On induction of apoptosis an interaction is observed of the nitric oxide signaling system with the sphingomyelin cycle, which is a source of a proapoptotic agent ceramide. Evidence is presented of an interaction of the sphingomyelin cycle enzymes and ceramide with nitric oxide and enzymes synthesizing nitric oxide. The role of a proinflammatory cytokine TNF-α in apoptosis and ischemia-reperfusion and mechanisms of its cytotoxic action, which involve nitric oxide, the sphingomyelin cycle, and lipid peroxidation are discussed. A comprehensive study of these signaling systems provides insight into the molecular mechanism of apoptosis during ischemia and allows us to consider new approaches for treatment of diseases associated with the activation of apoptosis.
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Affiliation(s)
- M A Shupik
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
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18
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Fenger M, Linneberg A, Jørgensen T, Madsbad S, Søbye K, Eugen-Olsen J, Jeppesen J. Genetics of the ceramide/sphingosine-1-phosphate rheostat in blood pressure regulation and hypertension. BMC Genet 2011; 12:44. [PMID: 21569466 PMCID: PMC3115901 DOI: 10.1186/1471-2156-12-44] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2011] [Accepted: 05/13/2011] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Several attempts to decipher the genetics of hypertension of unknown causes have been made including large-scale genome-wide association analysis (GWA), but only a few genes have been identified. Unsolved heterogeneity of the regulation of blood pressure and the shortcomings of the prevailing monogenic approach to capture genetic effects in a polygenic condition are the main reasons for the modest results. The level of the blood pressure is the consequence of the genotypic state of the presumably vast network of genes involved in regulating the vascular tonus and hence the blood pressure. Recently it has been suggested that components of the sphingolipid metabolism pathways may be of importance in vascular physiology. The basic metabolic network of sphingolipids has been established, but the influence of genetic variations on the blood pressure is not known. In the approach presented here the impact of genetic variations in the sphingolipid metabolism is elucidated by a two-step procedure. First, the physiological heterogeneity of the blood pressure is resolved by a latent class/structural equation modelling to obtain homogenous subpopulations. Second, the genetic effects of the sphingolipid metabolism with focus on de novo synthesis of ceramide are analysed. The model does not assume a particular genetic model, but assumes that genes operate in networks. RESULTS The stratification of the study population revealed that (at least) 14 distinct subpopulations are present with different propensity to develop hypertension. Main effects of genes in the de novo synthesis of ceramides were rare (0.14% of all possible). However, epistasis was highly significant and prevalent amounting to approximately 70% of all possible two-gene interactions. The phenotypic variance explained by the ceramide synthesis network were substantial in 4 of the subpopulations amounting to more than 50% in the subpopulation in which all subjects were hypertensive. Construction of the network using the epistatic values revealed that only 17% of the interactions detected were in the direct metabolic pathway, the remaining jumping one or more intermediates. CONCLUSIONS This study established the components of the ceramide/sphingosine-1-phosphate rheostat as central to blood pressure regulation. The results in addition confirm that epistasis is of paramount importance and is most conspicuous in the regulation of the rheostat network. Finally, it is shown that applying a simple case-control approach with single gene association analysis is bound to fail, short of identifying a few potential genes with small effects.
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Affiliation(s)
- Mogens Fenger
- Copenhagen University Hospital at Hvidovre, Department of Clinical Biochemistry, Genetics, and Molecular Biology, Kettegaard All 26, 2650 Hvidovre, Denmark.
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Ramirez-Sanchez I, Maya L, Ceballos G, Villarreal F. (-)-Epicatechin induces calcium and translocation independent eNOS activation in arterial endothelial cells. Am J Physiol Cell Physiol 2011; 300:C880-7. [PMID: 21209365 PMCID: PMC3074631 DOI: 10.1152/ajpcell.00406.2010] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 01/03/2011] [Indexed: 11/22/2022]
Abstract
The consumption of cacao-derived (i.e., cocoa) products provides beneficial cardiovascular effects in healthy subjects as well as individuals with endothelial dysfunction such as smokers, diabetics, and postmenopausal women. The vascular actions of cocoa are related to enhanced nitric oxide (NO) production. These actions can be reproduced by the administration of the cacao flavanol (-)-epicatechin (EPI). To further understand the mechanisms behind the vascular action of EPI, we investigated the effects of Ca(2+) depletion on endothelial nitric oxide (NO) synthase (eNOS) activation/phosphorylation and translocation. Human coronary artery endothelial cells were treated with EPI or with bradykinin (BK), a well-known Ca(2+)-dependent eNOS activator. Results demonstrate that both EPI and BK induce increases in intracellular calcium and NO levels. However, under Ca(2+)-free conditions, EPI (but not BK) is still capable of inducing NO production through eNOS phosphorylation at serine 615, 633, and 1177. Interestingly, EPI-induced translocation of eNOS from the plasmalemma was abolished upon Ca(2+) depletion. Thus, under Ca(2+)-free conditions, EPI can stimulate NO synthesis independent of calmodulin binding to eNOS and of its translocation into the cytoplasm. We also examined the effect of EPI on the NO/cGMP/vasodilator-stimulated phosphoprotein (VASP) pathway activation in isolated Ca(2+)-deprived canine mesenteric arteries. Results demonstrate that under these conditions, EPI induces the activation of this vasorelaxation-related pathway and that this effect is inhibited by pretreatment with nitro-L-arginine methyl ester, suggesting a functional relevance for this phenomenon.
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Abstract
PURPOSE OF REVIEW High-density lipoprotein (HDL) protects against atherosclerosis, transporting cholesterol from peripheral cells to the liver, where it is excreted into the bile. However, HDL also has prominent vascular protective effects. RECENT FINDINGS Recent studies have uncovered mechanisms through which HDL decreases vascular inflammation, boosts nitric oxide production, and inhibits thrombosis. The discovery that dysfunctional HDL can also have proinflammatory effects has uncovered a new aspect of HDL biology. SUMMARY Low-density lipoprotein is the primary target for drug therapy of dyslipidemias. Drugs that increase HDL also affect additional metabolic pathways. Development of selective drugs targeting key aspects of HDL metabolism may enable us to alter the composition of HDL and inhibit atherogenesis.
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Affiliation(s)
- Charles J Lowenstein
- Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA.
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21
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Andrews KL, Moore XL, Chin-Dusting JPF. Anti-atherogenic effects of high-density lipoprotein on nitric oxide synthesis in the endothelium. Clin Exp Pharmacol Physiol 2010; 37:736-42. [PMID: 20374256 DOI: 10.1111/j.1440-1681.2010.05387.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
1. The endothelium is critical in the control of vascular haemodynamics and haemostasis. Endothelial dysfunction, typically characterized by decreased nitric oxide bioavailability and response to endothelium-dependent agonists, is well accepted as a defining characteristic of early atherosclerosis. 2. Numerous epidemiological studies have reported that increased levels of circulating HDL are vasculoprotective and reduce the incidence of adverse cardiovascular events. Traditionally, these effects have been attributed to the ability of HDL to remove cholesterol from cells via reverse cholesterol transport. However, there is increasing evidence that the beneficial effects on the endothelium by HDL encompass its anti-inflammatory, antithrombotic and anti-oxidative properties, which include the release of nitric oxide (NO). 3. This review highlights recent findings on the importance of HDL in reducing atherosclerotic risk. We focus on the beneficial effects of HDL-induced NO release and how this relates to endothelial dysfunction and on the effect of HDL on vascular repair via endothelial progenitor cells.
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Affiliation(s)
- Karen L Andrews
- Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia
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22
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Spijkers LJA, Alewijnse AE, Peters SLM. Sphingolipids and the orchestration of endothelium-derived vasoactive factors: when endothelial function demands greasing. Mol Cells 2010; 29:105-11. [PMID: 20127284 DOI: 10.1007/s10059-010-0042-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 01/08/2010] [Indexed: 02/02/2023] Open
Abstract
Vasomotor tone is regulated by a complex interplay of a variety of extrinsic neurohumoral and intrinsic factors. It is the endothelium that has a major influence on smooth muscle cell tone via the release of intrinsic vasoactive factors and is therefore an important regulator of vasomotor tone. Sphingolipids are an emerging class of lipid mediators with important physiological properties. In the last two decades it has not only become increasingly clear that sphingolipid signaling plays a pivotal role in immune function, but also its role in the vascular system is now becoming more recognized. In this mini-review we will highlight the possible cross-talk between sphingolipids and intrinsic vasoactive factors released by the endothelium. Via this cross-talk sphingolipids can orchestrate vasomotor tone and may therefore also be involved in the pathophysiology of disease states associated with endothelial dysfunction.
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Affiliation(s)
- Léon J A Spijkers
- Department Pharmacology and Pharmacotherapy, Academic Medical Center, Amsterdam, The Netherlands
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23
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Park JY, Shin HK, Choi YW, Lee YJ, Bae SS, Han J, Kim CD. Gomisin A induces Ca2+-dependent activation of eNOS in human coronary artery endothelial cells. JOURNAL OF ETHNOPHARMACOLOGY 2009; 125:291-296. [PMID: 19577623 DOI: 10.1016/j.jep.2009.06.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 06/17/2009] [Accepted: 06/25/2009] [Indexed: 05/28/2023]
Abstract
AIM OF THE STUDY Gomisin A (GA) is a small molecular weight lignan contained in Fructus Schisandrae, the dried seed of Schisandra chinensis which is widely used as a tonic in traditional Korean medicine. We previously demonstrated that GA induces endothelium-dependent and -independent relaxation in rat thoracic aorta, however the signaling pathways involved was not clarified. In this study, we examined whether GA could actually induce nitric oxide (NO) production and clarified the mechanism in cultured human coronary artery endothelial cells (HCAEC). RESULTS Treatment of HCAEC with GA induced NO production in a time- and concentration-dependent manner in association with an enhanced endothelial NO synthase (eNOS) activity with an increased cytosolic translocation of eNOS. Both GA-induced NO production and eNOS activation were attenuated by pretreatment of the cells with EGTA, an extracellular Ca(2+) chelator, and BAPTA-AM, an intracellular Ca(2+) chelator, but not by LY 294002, a PI3-kinase/Akt inhibitor, suggesting involvement of Ca(2+). Furthermore, GA rapidly increased the intracellular Ca(2+) concentration, which was abolished in Ca(2+) free media. CONCLUSION Taken together, our results suggest that GA induces Ca(2+)-dependent activation and translocation of eNOS in HCAEC, events linked to NO production and thereby endothelial-dependent vasorelaxation.
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Affiliation(s)
- Ji Young Park
- Department of Pharmacology, School of Medicine, and MRC for Ischemic Tissue Regeneration and Medical Research Institute, Pusan National University, Yangsan, Gyeongnam 626-770, Republic of Korea
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Bismuth J, Chai H, Lin PH, Yao Q, Chen C. Lactosylceramide causes endothelial dysfunction in porcine coronary arteries and human coronary artery endothelial cells. Med Sci Monit 2009; 15:BR270-BR274. [PMID: 19721395 PMCID: PMC2927961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023] Open
Abstract
BACKGROUND Lactosylceramide (LacCer) is a member of the glycosphingolipid family, which has been implicated in the atherogenic process. The goal of this study was to determine the effects and molecular mechanisms of LacCer on endothelial functions in porcine coronary arteries and human coronary endothelial cells (HCAECs). MATERIAL/METHODS The vessel rings and HCAECs were treated with different concentrations of LacCer for 24 hours. Vasomotor function was studied using a myograph tension system in response to thromboxane A2 analog U46619, bradykinin and sodium nitroprusside (SNP). Superoxide anion production was determined using lucigenin-enhanced chemiluminescence. The expression of endothelial nitric oxide synthase (eNOS), NADPH oxidase subunit NOX4 and catalase was determined by real-time PCR. RESULTS LacCer (0.1, 1 and 10 microM) significantly decreased endothelium-dependent vasorelaxation (bradykinin) in porcine coronary artery rings in a concentration-dependent manner compared with untreated controls (P<0.05). High concentration of LacCer (10 microM) also reduced endothelium-independent vasorelaxation (SNP). However, LacCer did not affect vessel contraction (U46619). Antioxidant selenomethionine (SeMet) effectively reversed LacCer-induced endothelial dysfunction in the vessel rings. Furthermore, LacCer significantly increased superoxide anion production in the vessel rings in a concentration-dependent manner compared with untreated controls (P<0.05). In response to LacCer treatment, NOX4 mRNA levels were significantly increased, while the expression of catalase and eNOS was significantly decreased in HCAECs compared with controls (P<0.05). CONCLUSIONS LacCer causes endothelial dysfunction with potential mechanisms of the down-regulation of eNOS and increase of oxidative stress due to the activation of NADPH oxidase and inhibition of internal antioxidant catalase. This study suggests that LacCer may represent a risk factor to the vascular system and antioxidant SeMet may have clinical applications for prevention of vascular disease.
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Affiliation(s)
- Jean Bismuth
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX, U.S.A
| | - Hong Chai
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX, U.S.A
| | - Peter H. Lin
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX, U.S.A
- Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, U.S.A
| | - Qizhi Yao
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX, U.S.A
- Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, U.S.A
| | - Changyi Chen
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX, U.S.A
- Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, U.S.A
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Schwarz E, Prabakaran S, Whitfield P, Major H, Leweke FM, Koethe D, McKenna P, Bahn S. High throughput lipidomic profiling of schizophrenia and bipolar disorder brain tissue reveals alterations of free fatty acids, phosphatidylcholines, and ceramides. J Proteome Res 2008; 7:4266-77. [PMID: 18778095 DOI: 10.1021/pr800188y] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A mass spectrometry based high throughput approach was employed to profile white and gray matter lipid levels in the prefrontal cortex (Brodmann area 9) of 45 subjects including 15 schizophrenia and 15 bipolar disorder patients as well as 15 controls samples. We found statistically significant alterations in levels of free fatty acids and phosphatidylcholine in gray and white matter of both schizophrenia and bipolar disorder samples compared to controls. Also, ceramides were identified to be significantly increased in white matter of both neuropsychiatric disorders as compared to control levels. The patient cohort investigated in this study includes a number of drug naive as well as untreated patients, allowing the assessment of drug effects on lipid levels. Our findings indicate that while gray matter phosphatidylcholine levels were influenced by antipsychotic medication, this was not the case for phosphatidylcholine levels in white matter. Changes in free fatty acids or ceramides in either white or gray matter also did not appear to be influenced by antipsychotic treatment. To assess lipid profiles in the living patient, we also profiled lipids of 40 red blood cell samples, including 7 samples from drug naive first onset patients. We found significant alterations in the concentrations of free fatty acids as well as ceramide. Overall, our findings suggest that lipid abnormalities may be a disease intrinsic feature of both schizophrenia and bipolar disorder reflected by significant changes in the central nervous system as well as peripheral tissues.
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Affiliation(s)
- Emanuel Schwarz
- Institute of Biotechnology, University of Cambridge, Cambridge CB2 1QT, United Kingdom
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26
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Alewijnse AE, Peters SLM. Sphingolipid signalling in the cardiovascular system: good, bad or both? Eur J Pharmacol 2008; 585:292-302. [PMID: 18420192 DOI: 10.1016/j.ejphar.2008.02.089] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 01/21/2008] [Accepted: 02/06/2008] [Indexed: 12/25/2022]
Abstract
Sphingolipids are biologically active lipids that play important roles in various cellular processes and the sphingomyelin metabolites ceramide, sphingosine and sphingosine-1-phosphate can act as signalling molecules in most cell types. With the recent development of the immunosuppressant drug FTY720 (Fingolimod) which after phosphorylation in vivo acts as a sphingosine-1-phosphate receptor agonist, research on the role of sphingolipids in the immune and other organ systems was triggered enormously. Since it was reported that FTY720 induced a modest, but significant transient decrease in heart rate in animals and humans, the question was raised which pharmacological properties of drugs targeting sphingolipid signalling will affect cardiovascular function in vivo. The answer to this question will most likely also indicate what type of drug could be used to treat cardiovascular disease. The latter is becoming increasingly important because of the increasing population carrying characteristics of the metabolic syndrome. This syndrome is, amongst others, characterized by obesity, hypertension, atherosclerosis and diabetes. As such, individuals with this syndrome are at increased risk of heart disease. Now numerous studies have investigated sphingolipid effects in the cardiovascular system, can we speculate whether certain sphingolipids under specific conditions are good, bad or maybe both? In this review we will give a brief overview of the pathophysiological role of sphingolipids in cardiovascular disease. In addition, we will try to answer how drugs that target sphingolipid signalling will potentially influence cardiovascular function and whether these drugs would be useful to treat cardiovascular disease.
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Affiliation(s)
- Astrid E Alewijnse
- Department of Pharmacology and Pharmacotherapy, Academic Medical Center, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
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Bismuth J, Lin P, Yao Q, Chen C. Ceramide: a common pathway for atherosclerosis? Atherosclerosis 2008; 196:497-504. [PMID: 17963772 PMCID: PMC2924671 DOI: 10.1016/j.atherosclerosis.2007.09.018] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2007] [Revised: 09/08/2007] [Accepted: 09/13/2007] [Indexed: 10/22/2022]
Abstract
Plasma sphingomyelin concentration is correlated with the development of atherosclerosis. It has been found to exist in significantly higher concentrations in aortic plaque. This appears to have clinical relevance as well as it has been shown to be an independent predictor of coronary artery disease. Ceramide, the backbone of sphingolipids, is the key component which affects atherosclerotic changes through its important second-messenger role. This paper sheds light on some of the current literature supporting the significance of ceramide with respect to its interactions with lipids, inflammatory cytokines, homocysteine and matrix metalloproteinases. Furthermore, the potential therapeutic implications of modulating ceramide concentrations are also discussed.
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Affiliation(s)
- Jean Bismuth
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Texas
| | - Peter Lin
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Texas
| | - Qizhi Yao
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Texas
| | - Changyi Chen
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Texas
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Lepiller S, Laurens V, Bouchot A, Herbomel P, Solary E, Chluba J. Imaging of nitric oxide in a living vertebrate using a diamino-fluorescein probe. Free Radic Biol Med 2007; 43:619-27. [PMID: 17640572 DOI: 10.1016/j.freeradbiomed.2007.05.025] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Revised: 05/22/2007] [Accepted: 05/23/2007] [Indexed: 10/23/2022]
Abstract
Numerous approaches have been described to identify nitric oxide (NO), a free radical involved in various physiological and pathophysiological processes. One of these approaches is based on the use of chemical probes whose transformation by NO generates highly fluorescent derivatives, permitting detection of NO down to nanomolar concentrations. Here, we show that the cell-permeant diamino-fluorophore 4-amino-5-methylamino-2'-7'-difluoro-fluorescein diacetate (DAF-FM-DA) can be used to detect NO production sites in a living vertebrate, the zebrafish Danio rerio. The staining pattern obtained in larvae includes the bulbus arteriosus, forming bones, the notochord, and the caudal fin. The specificity of the signal was confirmed by its decrease in animals exposed to a NO scavenger or a NO synthase inhibitor and its increase in the presence of a NO donor. Using this method, NO production was observed to change along development in the notochord and the caudal fin whereas it remained stable in the bulbus arteriosus. Local changes in NO production in response to stressful conditions were also detected by this method. Altogether, labeling with DAF-FM DA is an efficient method to monitor changes in NO production in live zebrafish under physiological as well as pathophysiological conditions, suggesting applications to drug screening and molecular pharmacology.
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Affiliation(s)
- Sandrine Lepiller
- Inserm UMR 866, University of Burgundy, Institut Fédératif de Recherche Santé STIC, 6 Boulevard Gabriel, Dijon F-21000 Dijon, France
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Thomas S, Kotamraju S, Zielonka J, Harder DR, Kalyanaraman B. Hydrogen peroxide induces nitric oxide and proteosome activity in endothelial cells: a bell-shaped signaling response. Free Radic Biol Med 2007; 42:1049-61. [PMID: 17349932 PMCID: PMC2692187 DOI: 10.1016/j.freeradbiomed.2007.01.005] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Revised: 12/13/2006] [Accepted: 01/03/2007] [Indexed: 11/20/2022]
Abstract
We investigated nitric oxide (*NO)-mediated proteosomal activation in bovine aortic endothelial cells (BAEC) treated with varying fluxes of hydrogen peroxide (H(2)O(2)) generated from glucose/glucose oxidase (Glu/GO). Results revealed a bell-shaped *NO signaling response in BAEC treated with Glu/GO (2-20 mU/ml). GO treatment (2 mU/ml) enhanced endothelial nitric oxide synthase (eNOS) phosphorylation and *NO release in BAEC. With increasing GO concentrations, phospho eNOS and *NO levels decreased. Bell-shaped responses in proteasomal function and *NO induction were observed in BAEC treated with varying levels of GO (2-10 mU/ml). Proteosomal activation induced in GO-treated BAEC was inhibited by N(omega)-nitro-L-arginine-methyl ester pretreatment, suggesting that *NO mediates proteasomal activation. Intracellular *NO induced by H(2)O(2) was detected by isolating the 4,5-diaminoflourescein (DAF-2)/*NO/O(2)-derived "green fluorescent product" using the high-performance liquid chromatography-fluorescence technique, a more rigorous and quantitative methodology for detecting the DAF-2/*NO/O(2) reaction product. Finally, the relationships between H(2)O(2) flux, proteasomal activation/inactivation, endothelial cell survival, and apoptosis are discussed.
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Affiliation(s)
- Simmy Thomas
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226 USA
- Free Radical Research Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226 USA
| | - Srigiridhar Kotamraju
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226 USA
- Free Radical Research Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226 USA
| | - Jacek Zielonka
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226 USA
- Free Radical Research Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226 USA
| | - David R. Harder
- Free Radical Research Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226 USA
- Cardiovascular Research Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226 USA, 414-456-4000 (phone), 414-456-6512 (fax),
| | - B. Kalyanaraman
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226 USA
- Free Radical Research Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226 USA
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Mount PF, Kemp BE, Power DA. Regulation of endothelial and myocardial NO synthesis by multi-site eNOS phosphorylation. J Mol Cell Cardiol 2007; 42:271-9. [PMID: 16839566 DOI: 10.1016/j.yjmcc.2006.05.023] [Citation(s) in RCA: 379] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Revised: 05/03/2006] [Accepted: 05/31/2006] [Indexed: 02/07/2023]
Abstract
The controlled regulation of nitric oxide (NO) synthesis in endothelial cells and cardiomyocytes by the endothelial form of nitric oxide synthase (eNOS or NOS3) is essential for cardiovascular health. In recent years, a picture of complex and precise regulation of eNOS activity involving multi-site phosphorylation of specific serine and threonine residues has emerged. Regulation of endothelial NO synthesis by multi-site eNOS phosphorylation occurs in response to a wide variety of humoral, mechanical and pharmacological stimuli. This regulation involves numerous kinases and phosphatases, as well as interactions with other aspects of eNOS regulation such as Ca(2+) flux, protein-protein interactions and regulation of subcellular localization. Phosphorylation of eNOS-Ser(1177) close to the carboxy-terminal is a critical requirement for eNOS activation. In addition, phosphorylation of eNOS-Ser(633) in the flavin mononucleotide (FMN) binding domain also increases eNOS activity and appears particularly important for the maintenance of NO synthesis after initial activation by Ca(2+) flux and Ser(1177) phosphorylation. In contrast, NO synthesis is inhibited by phosphorylation of eNOS-Thr(495), which interferes with the binding of calmodulin to the eNOS calmodulin-binding domain. Regulated phosphorylation of eNOS also occurs at eNOS-Ser(114) and eNOS-Ser(615); however, the functions of these phosphorylation sites remain controversial. This review summarizes the present knowledge of the regulation of NO synthesis by multi-site eNOS phosphorylation and its relationship to other mechanisms of eNOS regulation. This progress in understanding important mechanisms controlling endothelial NO synthesis creates new opportunities to understand and potentially treat cardiovascular diseases characterized by deficient NO synthesis.
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Affiliation(s)
- Peter F Mount
- Department of Nephrology, Austin Health, Studley Road, Heidelberg 3084, Victoria, Australia.
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Oess S, Icking A, Fulton D, Govers R, Müller-Esterl W. Subcellular targeting and trafficking of nitric oxide synthases. Biochem J 2006; 396:401-9. [PMID: 16722822 PMCID: PMC1482820 DOI: 10.1042/bj20060321] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Unlike most other endogenous messengers that are deposited in vesicles, processed on demand and/or secreted in a regulated fashion, NO (nitric oxide) is a highly active molecule that readily diffuses through cell membranes and thus cannot be stored inside the producing cell. Rather, its signalling capacity must be controlled at the levels of biosynthesis and local availability. The importance of temporal and spatial control of NO production is highlighted by the finding that differential localization of NO synthases in cardiomyocytes translates into distinct effects of NO in the heart. Thus NO synthases belong to the most tightly controlled enzymes, being regulated at transcriptional and translational levels, through co- and post-translational modifications, by substrate availability and not least via specific sorting to subcellular compartments, where they are in close proximity to their target proteins. Considerable efforts have been made to elucidate the molecular mechanisms that underlie the intracellular targeting and trafficking of NO synthases, to ultimately understand the cellular pathways controlling the formation and function of this powerful signalling molecule. In the present review, we discuss the mechanisms and triggers for subcellular routing and dynamic redistribution of NO synthases and the ensuing consequences for NO production and action.
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Affiliation(s)
- Stefanie Oess
- *Institute of Biochemistry II, University of Frankfurt Medical School, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Ann Icking
- *Institute of Biochemistry II, University of Frankfurt Medical School, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - David Fulton
- †Vascular Biology Center and Pharmacology, Medical College of Georgia, 1459 Laney Walker Boulevard, Augusta, GA 30912-2500, U.S.A
| | - Roland Govers
- ‡INSERM U568, Faculté de Médecine, 28, avenue de Valombrose, 06107 Nice, France
| | - Werner Müller-Esterl
- *Institute of Biochemistry II, University of Frankfurt Medical School, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
- To whom correspondence should be addressed (email )
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Kim JA, Montagnani M, Koh KK, Quon MJ. Reciprocal relationships between insulin resistance and endothelial dysfunction: molecular and pathophysiological mechanisms. Circulation 2006; 113:1888-904. [PMID: 16618833 DOI: 10.1161/circulationaha.105.563213] [Citation(s) in RCA: 1147] [Impact Index Per Article: 60.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Endothelial dysfunction contributes to cardiovascular diseases, including hypertension, atherosclerosis, and coronary artery disease, which are also characterized by insulin resistance. Insulin resistance is a hallmark of metabolic disorders, including type 2 diabetes mellitus and obesity, which are also characterized by endothelial dysfunction. Metabolic actions of insulin to promote glucose disposal are augmented by vascular actions of insulin in endothelium to stimulate production of the vasodilator nitric oxide (NO). Indeed, NO-dependent increases in blood flow to skeletal muscle account for 25% to 40% of the increase in glucose uptake in response to insulin stimulation. Phosphatidylinositol 3-kinase-dependent insulin-signaling pathways in endothelium related to production of NO share striking similarities with metabolic pathways in skeletal muscle that promote glucose uptake. Other distinct nonmetabolic branches of insulin-signaling pathways regulate secretion of the vasoconstrictor endothelin-1 in endothelium. Metabolic insulin resistance is characterized by pathway-specific impairment in phosphatidylinositol 3-kinase-dependent signaling, which in endothelium may cause imbalance between production of NO and secretion of endothelin-1, leading to decreased blood flow, which worsens insulin resistance. Therapeutic interventions in animal models and human studies have demonstrated that improving endothelial function ameliorates insulin resistance, whereas improving insulin sensitivity ameliorates endothelial dysfunction. Taken together, cellular, physiological, clinical, and epidemiological studies strongly support a reciprocal relationship between endothelial dysfunction and insulin resistance that helps to link cardiovascular and metabolic diseases. In the present review, we discuss pathophysiological mechanisms, including inflammatory processes, that couple endothelial dysfunction with insulin resistance and emphasize important therapeutic implications.
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Affiliation(s)
- Jeong-a Kim
- Diabetes Unit, National Center for Complementary and Alternative Medicine, National Institutes of Health, Bethesda, MD 20892-1632, USA
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Gulbins E, Li PL. Physiological and pathophysiological aspects of ceramide. Am J Physiol Regul Integr Comp Physiol 2006; 290:R11-26. [PMID: 16352856 DOI: 10.1152/ajpregu.00416.2005] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Activation of cells by receptor- and nonreceptor-mediated stimuli not only requires a change in the activity of signaling proteins but also requires a reorganization of the topology of the signalosom in the cell. The cell membrane contains distinct domains, rafts that serve the spatial organization of signaling molecules in the cell. Many receptors or stress stimuli transform rafts by the generation of ceramide. These stimuli activate the acid sphingomyelinase and induce a translocation of this enzyme onto the extracellular leaflet of the cell membrane. Surface acid sphingomyelinase generates ceramide that serves to fuse small rafts and to form large ceramide-enriched membrane platforms. These platforms cluster receptor molecules, recruit intracellular signaling molecules to aggregated receptors, and seem to exclude inhibitory signaling factors. Thus ceramide-enriched membrane platforms do not seem to be part of a specific signaling pathway but may facilitate and amplify the specific signaling elicited by the cognate stimulus. This general function may enable these membrane domains to be critically involved in the induction of apoptosis by death receptors and stress stimuli, bacterial and viral infections of mammalian cells, and the regulation of cardiovascular functions.
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Affiliation(s)
- Erich Gulbins
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany.
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Affiliation(s)
- Sae-Chul Kim
- Department of Urology, Chung-Ang University College of Medicine, Seoul, Korea
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35
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Pott C, Steinritz D, Bölck B, Mehlhorn U, Brixius K, Schwinger RHG, Bloch W. eNOS translocation but not eNOS phosphorylation is dependent on intracellular Ca2+ in human atrial myocardium. Am J Physiol Cell Physiol 2005; 290:C1437-45. [PMID: 16338973 DOI: 10.1152/ajpcell.00005.2005] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In endothelial cells, two ways of endothelial nitric oxide (NO) synthase (eNOS) activation are known: 1) translocation and 2) Akt-dependent phosphorylation of the enzyme at Ser(1177) (Ser(1177) eNOS). We have recently shown that agonist-induced Ser(1177) eNOS phosphorylation also occurs in human myocardium (10). In this study, we investigated the Ca(2+) dependency of these two mechanisms in human atrium. Therefore, atrial tissue was obtained from patients who underwent coronary artery bypass operations. In immunohistochemical experiments, the translocated form of eNOS and phosphorylated Ser(1177) eNOS were labeled using specific antibodies. eNOS translocation was measured in the absence and presence of the Ca(2+) chelator BAPTA before and after application of BRL 37344 (BRL), a beta(3)-adrenoceptor agonist that increases eNOS activity (34). In the absence of BAPTA, BRL time dependently increased the staining intensity of translocated eNOS, whereas in the presence of BAPTA, this effect was blunted. In contrast, BRL clearly increased the staining of phosphorylated Ser(1177) eNOS even in the presence of BAPTA. This observation was confirmed using Western blot analysis. Using the NO-sensitive dye diaminofluorescein, we have demonstrated that BRL induced a strong NO release. This effect was completely abolished in the presence of BAPTA but was unaffected by LY-292004, an inhibitor of phosphatidylinositol 3-kinase activity and eNOS phosphorylation. Although Ca(2+) dependent, neither the translocation of eNOS nor NO release was changed by the adenylate cyclase activator forskolin. In conclusion, 1) in human atrial myocardium, BRL-induced eNOS translocation but not Ser(1177) eNOS phosphorylation is dependent on intracellular Ca(2+). 2) In atrial myocardium, eNOS-translocation and not Ser(1177) eNOS phosphorylation is responsible for generating the main amount of NO. 3) Although Ca(2+) dependent, eNOS translocation and NO release could not be mimicked by adenylate cyclase activation as a mediator of beta-adrenergic stimulation.
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Affiliation(s)
- Christian Pott
- Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Institutsgebäude 1, 9.OG, Carl-Diem-Weg 6, Rm. 911, D-50933 Cologne, Germany
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Lerouet D, Jafarian-Tehrani M, Louin G, Palmier B, Bonnefont-Rousselot D, Plotkine M, Margaill I. Lack of iNOS induction in a severe model of transient focal cerebral ischemia in rats. Exp Neurol 2005; 195:218-28. [PMID: 15935350 DOI: 10.1016/j.expneurol.2005.05.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2005] [Revised: 04/20/2005] [Accepted: 05/01/2005] [Indexed: 11/24/2022]
Abstract
Calcium-independent nitric oxide synthase (NOS) activity has been reported in ischemic brains and usually attributed to the inducible isoform, iNOS. Because calcium-independent mechanisms have recently been shown to regulate the constitutive calcium-dependent NOS, we proposed to confirm the presence of iNOS activity in our model of transient focal cerebral ischemia in rats. Our initial results showed that, in our model, ischemia induced an important increase in brain calcium concentration. Consequently, the determination of calcium-independent NOS activity required a higher concentration of calcium chelator than classically used in the NOS assay. In these conditions, calcium-independent NOS activity was not observed after ischemia. Moreover, our ischemia was associated with neither iNOS protein expression, measured by Western blotting, nor increased NO production, evaluated by its metabolites (nitrate/nitrite). Our results demonstrate that iNOS activity may be overestimated due to increased brain calcium concentration in ischemic conditions and also that iNOS is not systematically induced after cerebral ischemia.
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Affiliation(s)
- Dominique Lerouet
- Laboratoire de Pharmacologie (UPRES EA 2510), Université René Descartes, 4 avenue de l'Observatoire, 75006 Paris, France
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Mimeault M, Jouy N, Depreux P, Hénichart JP. Synergistic antiproliferative and apoptotic effects induced by mixed epidermal growth factor receptor inhibitor ZD1839 and nitric oxide donor in human prostatic cancer cell lines. Prostate 2005; 62:187-99. [PMID: 15389789 DOI: 10.1002/pros.20138] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND The specific inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase, ZD1839 induces potent antitumoral effects on several advanced cancer types. The present study was undertaken to determine whether the combination of ZD1839 with an agent donating nitric oxide (NO(*)), sodium nitroprusside (SNP) results in a synergy of anticarcinogenic responses on metastatic prostate cancer (PC) cells. METHODS The antiproliferative and apoptotic/necrotic effects of ZD1839 and SNP alone or in combination were estimated on EGF- and serum-stimulated LNCaP, DU145, and PC3 cells by MTT growth tests, trypan blue dye exclusion method, and flow cytometric analyses. Moreover, the cellular ceramide levels were evaluated by the diacylglycerol kinase enzymatic method and the amounts of cytosolic cytochrome c by ELISA assays. RESULTS ZD1839 and SNP alone or in combination at lower concentrations induced an inhibition of EGF- and serum-stimulated growth of LNCaP, DU145, and PC3 concomitant with an arrest in the G1 phase of cellular cycle. Interestingly, the mixed ZD1839 and SNP also caused a more substantial apoptotic/necrotic death of these PC cells as compared to drugs alone. Moreover, we have observed that an inhibition of acidic sphingomyelinase, hydrogen peroxide (H(2)O(2)) accumulation and caspase cascades results in a significant reduction of apoptotic/necrotic death induced by mixed ZD1839 and SNP in EGF-stimulated PC3 cells. In addition, the combined ZD1839 plus SNP also induced a higher cellular ceramide and reactive oxygen species (ROS) production, mitochondrial transmembrane potential decrease, and cytochrome c amount released into cytosol as compared to drugs alone. CONCLUSIONS The simultaneous use of EGFR inhibitor and compound releasing NO(*) might lead to a synergy in the ceramide and ROS production which might cause cellular membrane damages resulting in a massive apoptotic/necrotic death of metastatic PC cells.
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Affiliation(s)
- Murielle Mimeault
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA
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Rodriguez J, Specian V, Maloney R, Jourd'heuil D, Feelisch M. Performance of diamino fluorophores for the localization of sources and targets of nitric oxide. Free Radic Biol Med 2005; 38:356-68. [PMID: 15629864 DOI: 10.1016/j.freeradbiomed.2004.10.036] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2004] [Revised: 10/15/2004] [Accepted: 10/22/2004] [Indexed: 01/14/2023]
Abstract
An emergent approach to the detection of nitric oxide (NO) in tissues relies on the use of fluorescence probes that are activated by products of NO autoxidation. Here we explore the performance of the widely used NO probe 4,5-diaminofluorescein diacetate (DAF-2 DA) for the localization of sources of NO in rat aortic tissue, either from endogenous NO synthesis or from chemically or photolytically released NO from targets of nitrosation/nitrosylation. Of importance toward understanding the performance of this probe in tissues is the finding that, with incubation conditions commonly used in the literature (10 microM DAF-2 DA), intracellular DAF-2 accumulates to concentrations that approach the millimolar range. Whereas such high probe concentrations do not interfere with NO release or signaling, they help to clarify why DAF-2 nitrosation is possible in the presence of endogenous nitrosation scavengers (e.g., ascorbate and glutathione). The gain attained with such elevated concentrations is, however, mitigated by associated high levels of background autofluorescence from the probe. This, together with tissue autofluorescence, limits the sensitivity of the probe to low-micromolar levels of accumulated DAF-2 triazole (DAF-2 T), the activated form of the probe, which is higher than the concentrations of most endogenous nitrosation/nitrosylation products found in tissues. We further show that the compartmentalization of DAF-2 around elastic fibers further limits its potential to characterize the site of NO production at the subcellular level. Moreover, we find that reaction of DAF-2 with HgCl(2) and other commonly employed reagents is associated with spectral changes that may be misinterpreted as NO signals. Finally, UV illumination can lead to high levels of nitrosating species that interfere with NO detection from enzymatic sources. These findings indicate that while DAF-2 may still represent an important tool for the localization of NO synthesis, provided important pitfalls and limitations are taken into consideration, it is not suited for the detection of basally generated nitrosation/nitrosylation products.
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Affiliation(s)
- Juan Rodriguez
- Department of Molecular and Cellular Physiology, LSU Health Sciences Center, Shreveport, LA 71130, USA
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Mogami K, Kishi H, Kobayashi S. Sphingomyelinase causes endothelium-dependent vasorelaxation through endothelial nitric oxide production without cytosolic Ca2+elevation. FEBS Lett 2004; 579:393-7. [PMID: 15642349 DOI: 10.1016/j.febslet.2004.11.100] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2004] [Revised: 09/18/2004] [Accepted: 11/02/2004] [Indexed: 11/21/2022]
Abstract
Neutral sphingomyelinase (N-SMase) elevated nitric oxide (NO) production without affecting intracellular Ca(2+) concentration ([Ca(2+)](i)) in endothelial cells in situ on aortic valves, and induced prominent endothelium-dependent relaxation of coronary arteries, which was blocked by N(omega)-monomethyl-L-arginine, a NO synthase (NOS) inhibitor. N-SMase induced translocation of endothelial NOS (eNOS) from plasma membrane caveolae to intracellular region, eNOS phosphorylation on serine 1179, and an increase of ceramide level in endothelial cells. Membrane-permeable ceramide (C(8)-ceramide) mimicked the responses to N-SMase. We propose the involvement of N-SMase and ceramide in Ca(2+)-independent eNOS activation and NO production in endothelial cells in situ, linking to endothelium-dependent vasorelaxation.
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Affiliation(s)
- Kimiko Mogami
- Department of Molecular Physiology, Yamaguchi University School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi 755-8505, Japan
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Arena S, Pattarozzi A, Corsaro A, Schettini G, Florio T. Somatostatin receptor subtype-dependent regulation of nitric oxide release: involvement of different intracellular pathways. Mol Endocrinol 2004; 19:255-67. [PMID: 15388796 DOI: 10.1210/me.2004-0280] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We reported previously that, in addition to direct effects, somatostatin (SST) affects tumor growth inhibiting the tumoral neoangiogenesis, via an interference with NO synthesis. Here, we analyzed the effects of SST on nitric oxide (NO) production induced by different agonists [basic fibroblast growth factor (bFGF), insulin, cholecystokinin (CCK)] and the intracellular signaling involved, using Chinese hamster ovary-k1 cells stably transfected with individual SSTR1-SSTR4. bFGF and insulin induced endothelial nitric oxide synthase activity via the generation of ceramide or the Akt-dependent phosphorylation of endothelial nitric oxide synthase, respectively. CCK regulates neuronal nitric oxide synthase activity in a Ca++-dependent manner. SST inhibited NO production stimulated by bFGF through SST receptor 1 (SSTR1), SSTR2, and SSTR3 and by CCK through SSTR2 and SSTR3. In all the cell lines, SST treatment did not modify NO synthesis induced by insulin. SSTR4 activation was not effective on any of the stimuli tested. The effects on bFGF-induced NO production were downstream from receptor phosphorylation and ceramide synthesis. SSTR2 and -3 on CCK activity were related to the inhibition of intracellular Ca++ mobilization, whereas the lack of effects on insulin was paralleled by the absence of SST activity on Akt phosphorylation. These data, identifying for the first time a selective receptor subtype-inhibitory role of SST on NO generation, may open new perspectives in the use of SST agonists to control tumoral angiogenesis.
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Affiliation(s)
- Sara Arena
- Section of Pharacology, Department of Oncology, Biology and Genetics, University of Genova, and Pharmacology and Neuroscience, National Institute for Cancer Research (IST), 16132 Genova, Italy
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41
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Abstract
The endothelium is a dynamic organ that secretes several biologically active substances and plays a major functional role in the health of an organism in both physiological and pathological conditions. For instance, the endothelium is involved in control of the exchange of plasma and tissue biomolecules, regulation of vessel tone, inflammation, lipid metabolism, vessel growth and remodeling, and modulation of coagulation and fibrinolysis. The endothelium generates nitric oxide, which is a key regulator of vasodilation and plays important roles in preventing, or in some cases promoting, numerous cardiovascular diseases. Several recent studies have examined the interplay between lipids and nitric oxide generation, especially in relation to atherosclerosis. The endothelium is continuously exposed to circulating lipids in the form of lipoproteins and protein carriers that may have a direct impact on nitric oxide synthesis and function. The purpose of this review is to illustrate some of the recent findings that link lipids (plasma and cellular) to nitric oxide generation (see Fig. 1).
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Affiliation(s)
- Gentle Chikani
- Department of Pediatrics, University of Kentucky Medical School, Lexington, Kentucky 40536-0230, USA
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42
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Louin G, Besson VC, Royo NC, Bonnefont-Rousselot D, Marchand-Verrecchia C, Plotkine M, Jafarian-Tehrani M. Cortical calcium increase following traumatic brain injury represents a pitfall in the evaluation of Ca2+-independent NOS activity. J Neurosci Methods 2004; 138:73-9. [PMID: 15325114 DOI: 10.1016/j.jneumeth.2004.03.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2004] [Revised: 03/01/2004] [Accepted: 03/08/2004] [Indexed: 12/16/2022]
Abstract
In this report, our findings highlighted the presence of a high level of calcium in the cortex following traumatic brain injury (TBI) in a rat model of fluid percussion-induced brain injury. This calcium increase represents a pitfall in the assessment of Ca2+-independent nitric oxide synthase (NOS) activity supposed to play a role in the secondary brain lesion following TBI. The so-called Ca2+-independent NOS activity measured in the injured cortex 72 h after TBI had the pharmacological profile of a Ca2+-dependent NOS and was therefore inhibited with a supplement of calcium chelator. The remaining activity was very low and iNOS protein was hardly immunodetected on the same sample used for NOS activity assay. The concentration of calcium chelator used in the assay should be revised and adjusted consequently to make sure that the calcium-free condition is achieved for the assay. Otherwise, the findings tend towards an overestimation of Ca2+-independent and underestimation of Ca2+-dependent NOS activities. The revised Ca2+-independent NOS activity assay was then tested, in relation with the amount of iNOS protein, in a model of LPS-induced neuroinflammation. Taken together, precautions should be taken when assessing the Ca2+-independent enzymatic activity in cerebral tissue after a brain insult.
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Affiliation(s)
- Gaëlle Louin
- Laboratoire de Pharmacologie (UPRES EA 2510), Université René Descartes, 4 Avenue de l'Observatoire, 75270 Paris Cedex 06, France
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43
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Abstract
The sphingolipid ceramide mediates a variety of stress responses, including vascular inflammation and thrombosis. Activated endothelial cells release Weibel-Palade bodies, granules containing von Willebrand factor (vWF) and P-selectin, which induce leukocyte rolling and platelet adhesion and aggregation. We hypothesized that ceramide induces vascular inflammation and thrombosis in part by triggering Weibel-Palade body exocytosis. We added ceramide to human aortic endothelial cells and assayed Weibel-Palade body exocytosis by measuring the concentration of vWF released into the media. Exogenous ceramide induces vWF release from endothelial cells in a dose-dependent manner. Activators of endogenous ceramide production, neutral sphingomyelinase, or tumor necrosis factor-α also induce Weibel-Palade body exocytosis. We next studied NO effects on ceramide-induced Weibel-Palade body exocytosis because NO can inhibit vascular inflammation. The NO donor
S
-nitroso-
N
-acetylpenicillamine decreases ceramide-induced vWF release in a dose-dependent manner, whereas the NO synthase inhibitor
N
G
-nitro-
l
-arginine methyl ester increases ceramide-induced vWF release. In summary, our findings show that endogenous ceramide triggers Weibel-Palade body exocytosis, and that endogenous NO inhibits ceramide-induced exocytosis. These data suggest a novel mechanism by which ceramide induces vascular inflammation and thrombosis.
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Affiliation(s)
- Rinky Bhatia
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Md 21205, USA
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44
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Abstract
Nitric oxide (NO) is a gaseous free radical that serves cell signaling, cellular energetics, host defense, and inflammatory functions in virtually all cells. In the kidney and vasculature, NO plays fundamental roles in the control of systemic and intrarenal hemodynamics, the tubuloglomerular feedback response, pressure natriuresis, release of sympathetic neurotransmitters and renin, and tubular solute and water transport. NO is synthesized from L-arginine by NO synthases (NOS). Because of its high chemical reactivity and high diffusibility, NO production by each of the 3 major NOS isoforms is regulated tightly at multiple levels from gene transcription to spatial proximity near intended targets to covalent modification and allosteric regulation of the enzyme itself. Many of these regulatory mechanisms have yet to be tested in renal cells. The NOS isoforms are distributed differentially and regulated in the kidney, and there remains some controversy over the specific expression of functional protein for the NOS isoforms in specific renal cell populations. Mice with targeted deletion of each of the NOS isoforms have been generated, and these each have unique phenotypes. Studies of the renal and vascular phenotypes of these mice have yielded important insights into certain vascular diseases, ischemic acute renal failure, the tubuloglomerular feedback response, and some mechanisms of tubular fluid and electrolyte transport, but thus far have been underexploited. This review explores the collective knowledge regarding the structure, regulation, and function of the NOS isoforms gleaned from various tissues, and highlights the progress and gaps in understanding in applying this information to renal and vascular physiology.
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Affiliation(s)
- Bruce C Kone
- University of Texas Health Sciences Center at Houston, 77030, USA.
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45
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Matsunaga T, Kotamraju S, Kalivendi SV, Dhanasekaran A, Joseph J, Kalyanaraman B. Ceramide-induced Intracellular Oxidant Formation, Iron Signaling, and Apoptosis in Endothelial Cells. J Biol Chem 2004; 279:28614-24. [PMID: 15102832 DOI: 10.1074/jbc.m400977200] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sphingolipid ceramide (N-acetylsphingosine), a bioactive second messenger lipid, was shown to activate reactive oxygen species (ROS), mitochondrial oxidative damage, and apoptosis in neuronal and vascular cells. The proapoptotic effects of tumor necrosis factor-alpha, hypoxia, and chemotherapeutic drugs were attributed to increased ceramide formation. Here we investigated the protective role of nitric oxide (.NO) during hydrogen peroxide (H(2)O(2))-mediated transferrin receptor (TfR)-dependent iron signaling and apoptosis in C(2)-ceramide (C(2)-cer)-treated bovine aortic endothelial cells (BAECs). Addition of C(2)-cer (5-20 microm) to BAECs enhanced .NO generation. However, at higher concentrations of C(2)-cer (> or =20 microm), .NO generation did not increase proportionately. C(2)-cer (20-50 microm) also resulted in H(2)O(2)-mediated dichlorodihydrofluorescein oxidation, reduced glutathione depletion, aconitase inactivation, TfR overexpression, TfR-dependent uptake of (55)Fe, release of cytochrome c from mitochondria into cytosol, caspase-3 activation, and DNA fragmentation. N(w)-Nitro-l-arginine methyl ester (l-NAME), a nonspecific inhibitor of nitricoxide synthases, augmented these effects in BAECs at much lower (i.e. nonapoptotic) concentrations of C(2)-cer. The 26 S proteasomal activity in BAECs was slightly elevated at lower concentrations of C(2)-cer (< or =10 microm) but was greatly suppressed at higher concentrations (>10 microm). Intracellular scavengers of H(2)O(2), cell-permeable iron chelators, anti-TfR receptor antibody, or mitochondria-targeted antioxidant greatly abrogated C(2)-cer- and/or l-NAME-induced oxidative damage, iron signaling, and apoptosis. We conclude that C(2)-cer-induced H(2)O(2) and TfR-dependent iron signaling are responsible for its prooxidant and proapoptotic effects and that .NO exerts an antioxidative and cytoprotective role.
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Affiliation(s)
- Toshiyuki Matsunaga
- Department of Biophysics and Free Radical Research Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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46
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SenBanerjee S, Lin Z, Atkins GB, Greif DM, Rao RM, Kumar A, Feinberg MW, Chen Z, Simon DI, Luscinskas FW, Michel TM, Gimbrone MA, García-Cardeña G, Jain MK. KLF2 Is a novel transcriptional regulator of endothelial proinflammatory activation. ACTA ACUST UNITED AC 2004; 199:1305-15. [PMID: 15136591 PMCID: PMC2211816 DOI: 10.1084/jem.20031132] [Citation(s) in RCA: 555] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The vascular endothelium is a critical regulator of vascular function. Diverse stimuli such as proinflammatory cytokines and hemodynamic forces modulate endothelial phenotype and thereby impact on the development of vascular disease states. Therefore, identification of the regulatory factors that mediate the effects of these stimuli on endothelial function is of considerable interest. Transcriptional profiling studies identified the Kruppel-like factor (KLF)2 as being inhibited by the inflammatory cytokine interleukin-1β and induced by laminar shear stress in cultured human umbilical vein endothelial cells. Overexpression of KLF2 in umbilical vein endothelial cells robustly induced endothelial nitric oxide synthase expression and total enzymatic activity. In addition, KLF2 overexpression potently inhibited the induction of vascular cell adhesion molecule-1 and endothelial adhesion molecule E-selectin in response to various proinflammatory cytokines. Consistent with these observations, in vitro flow assays demonstrate that T cell attachment and rolling are markedly attenuated in endothelial monolayers transduced with KLF2. Finally, our studies implicate recruitment by KLF2 of the transcriptional coactivator cyclic AMP response element–binding protein (CBP/p300) as a unifying mechanism for these various effects. These data implicate KLF2 as a novel regulator of endothelial activation in response to proinflammatory stimuli.
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Affiliation(s)
- Sucharita SenBanerjee
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St., Boston, MA 02115, USA
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47
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Abstract
In mammalian cells, formation of nitric oxide (NO) is catalysed by a family of enzymes termed NO synthases (NOS). There are three isoforms of this enzyme, NOS I, II and III. NOS III was originally cloned and identified in endothelial cells; thus this isoform is commonly called endothelial NOS (eNOS). The physiological role of NO produced by eNOS has been documented in most organs, including the brain, lung, cardiovascular system, kidney, liver, gastrointestinal tract and reproductive organs. The bioavailability of NO in these tissues is determined by the balance between its rate of production and degradation. The rate of NO production by eNOS is ultimately dependent on the activity of the enzyme. In the past years, co- and post-translational modifications such as myristoylation, palmitoylation, phosphorylation, protein-protein interactions and subcellular localization have been shown to play an important role in determining eNOS activity. In order to maintain specificity, the production of most signalling molecules occurs in an organized spatial and temporal pattern. Spatial localization of eNOS has been shown to be regulated by different mechanisms that control its targeting from the Golgi apparatus to the plasma membrane, correct compartmentalization within the membrane, and internalization from the plasma membrane to the cytoplasm after activation. Thus, regulated localization and trafficking of eNOS may be essential in regulating enzyme activity and maintaining the spatial and temporal organization of NO signalling in different cell types.
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Affiliation(s)
- P A Ortiz
- Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, MI 48202, USA
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48
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Chen DB, Bird IM, Zheng J, Magness RR. Membrane estrogen receptor-dependent extracellular signal-regulated kinase pathway mediates acute activation of endothelial nitric oxide synthase by estrogen in uterine artery endothelial cells. Endocrinology 2004; 145:113-25. [PMID: 14512434 DOI: 10.1210/en.2003-0547] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Rapid uterine vasodilatation after estrogen administration is believed to be mediated by endothelial production of nitric oxide (NO) via endothelial NO synthase (eNOS). However, the mechanism(s) by which estrogen activates eNOS in uterine artery endothelial cells (UAEC) is unknown. In this study, we observed that estradiol-17beta (E2) and E2-BSA rapidly (<2 min) increased total NOx production in UAEC in vitro. This was associated with rapid eNOS phosphorylation and activation but was unaltered by pretreatment with actinomycin-D. Estrogen receptor-alpha protein was detectable in isolated plasma membrane proteins by immunoblotting, and E2-BSA-fluorescein isothiocyanate binding was evident on the plasma membrane of UAEC. E2 did not mobilize intracellular Ca2+, but E2 and ionomycin in combination induced greater eNOS phosphorylation than either E2 or ionomycin alone. E2 did not stimulate rapid Akt phosphorylation. E2 stimulated rapid ERK2/1 activation in a time- and dose-dependent manner, with maximal responses observed at 5-10 min with E2 (10 nm to 1 microm) treatment. Acute activation of eNOS and NOx production by E2 could be inhibited by PD98059 but not by LY294002. When E2-BSA was applied, similar responses in NOx production, eNOS, and ERK2/1 activation to those of E2 were achieved. In addition, E2 and E2-BSA-induced ERK2/1 activation and ICI 182,780 could inhibit NOx production by E2. Thus, acute activation of eNOS to produce NO in UAEC by estrogen is at least partially through an ERK pathway, possibly via estrogen receptor localized on the plasma membrane. This pathway may provide a novel mechanism for NO-mediated rapid uterine vasodilatation by estrogen.
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Affiliation(s)
- Dong-Bao Chen
- Department of Reproductive Medicine, University of California San Diego, La Jolla, California 92093-0802, USA.
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49
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Clementi E, Borgese N, Meldolesi J. Interactions between nitric oxide and sphingolipids and the potential consequences in physiology and pathology. Trends Pharmacol Sci 2003; 24:518-23. [PMID: 14559403 DOI: 10.1016/j.tips.2003.08.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Emilio Clementi
- Department of Pharmaco-Biology, University of Calabria, 87036 Rende, Italy.
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50
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Matsumoto A, Comatas KE, Liu L, Stamler JS. Screening for nitric oxide-dependent protein-protein interactions. Science 2003; 301:657-61. [PMID: 12893946 DOI: 10.1126/science.1079319] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Because nitric oxide (NO) may be a ubiquitous regulator of cellular signaling, we have modified the yeast two-hybrid system to explore the possibility of NO-dependent protein-protein interactions. We screened for binding partners of procaspase-3, a protein implicated in apoptotic signaling pathways, and identified multiple NO-dependent interactions.Two such interactions, with acid sphingomyelinase and NO synthase, were shown to occur in mammalian cells dependent on endogenous NO. Nitrosylation may thus provide a broad-based mechanism for regulating interactions between proteins. If so, systematic proteomic analyses in which redox state and NO bioavailability are carefully controlled will reveal a large array of novel interactions.
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Affiliation(s)
- Akio Matsumoto
- Howard Hughes Medical Institute and Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
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