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Gondal MUR, Mehmood RS, Khan RP, Malik J. Atrial myopathy. Curr Probl Cardiol 2024; 49:102381. [PMID: 38191102 DOI: 10.1016/j.cpcardiol.2024.102381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Accepted: 01/04/2024] [Indexed: 01/10/2024]
Abstract
This paper delves into the progressive concept of atrial myopathy, shedding light on its development and its impact on atrial characteristics. It extensively explores the intricate connections between atrial myopathy, atrial fibrillation (AF), and strokes. Researchers have sought additional contributors to AF-related strokes due to the absence of a clear timing correlation between paroxysmal AF episodes and strokes in patients with cardiac implantable electronic devices. Through various animal models and human investigations, a close interrelation among aging, inflammation, oxidative stress, and stretching mechanisms has been identified. These mechanisms contribute to fibrosis, alterations in electrical properties, autonomic remodeling, and a heightened pro-thrombotic state. These interconnected factors establish a detrimental cycle, exacerbating atrial myopathy and elevating the risk of sustained AF and strokes. By emphasizing the significance of atrial myopathy and the risk of strokes that are distinct from AF, the paper also discusses methods for identifying patients with atrial myopathy. Moreover, it proposes an approach to incorporate the concept of atrial myopathy into clinical practice to guide anticoagulation decisions in individuals with AF.
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Affiliation(s)
| | - Raja Sadam Mehmood
- Department of Medicine, Shifa International Hospital, Islamabad, Pakistan
| | | | - Jahanzeb Malik
- Department of Cardiovascular Medicine, Cardiovascular Analytics Group, Islamabad, Pakistan.
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2
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Amić A, Mastiľák Cagardová D. A DFT Study on the Kinetics of HOO •, CH 3OO •, and O 2•- Scavenging by Quercetin and Flavonoid Catecholic Metabolites. Antioxidants (Basel) 2023; 12:1154. [PMID: 37371883 DOI: 10.3390/antiox12061154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 05/19/2023] [Accepted: 05/23/2023] [Indexed: 06/29/2023] Open
Abstract
Reaction kinetics have been theoretically examined to ascertain the potency of quercetin (Q) and flavonoid catecholic metabolites 1-5 in the inactivation of HOO•, CH3OO•, and O2•- under physiological conditions. In lipidic media, the koverallTST/Eck rate constants for the proton-coupled electron transfer (PCET) mechanism indicate the catecholic moiety of Q and 1-5 as the most important in HOO• and CH3OO• scavenging. 5-(3,4-Dihydroxyphenyl)-γ-valerolactone (1) and alphitonin (5) are the most potent scavengers of HOO• and CH3OO•, respectively. The koverallMf rate constants, representing actual behavior in aqueous media, reveal Q as more potent in the inactivation of HOO• and CH3OO• via single electron transfer (SET). SET from 3-O- phenoxide anion of Q, a structural motif absent in 1-5, represents the most contributing reaction path to overall activity. All studied polyphenolics have a potency of O2•- inactivation via a concerted two-proton-coupled electron transfer (2PCET) mechanism. The obtained results indicate that metabolites with notable radical scavenging potency, and more bioavailability than ingested flavonoids, may contribute to human health-promoting effects ascribed to parent molecules.
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Affiliation(s)
- Ana Amić
- Department of Chemistry, Josip Juraj Strossmayer University of Osijek, Ulica cara Hadrijana 8A, 31000 Osijek, Croatia
| | - Denisa Mastiľák Cagardová
- Institute of Physical Chemistry and Chemical Physics, Department of Chemical Physics, Slovak University of Technology in Bratislava, Radlinského 9, SK-812 37 Bratislava, Slovakia
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3
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Hussien Abou Baker D, Ahmed Ibrahim E, Abd El-Rhaman Salama Z. Citrus Peels as a Source of Bioactive Compounds with Industrial and Therapeutic Applications. PHENOLIC COMPOUNDS - CHEMISTRY, SYNTHESIS, DIVERSITY, NON-CONVENTIONAL INDUSTRIAL, PHARMACEUTICAL AND THERAPEUTIC APPLICATIONS 2022. [DOI: 10.5772/intechopen.99591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
Agriculture wastes are considered a good starting point to discover for new drugs all over the world. In this context, Agriculture wastes contain millions of compounds to be screened to find bioactive compounds responsible for the activity to be used in drugs. Citrus agriculture is one of the most important commercial and industrial agricultural activities in the world. The peel waste of Citrus species is a rich source of bioactive compounds such as essential oils, flavones, polyphenols, and pigment. Citrus peel has been widely used in the medicine industry. The waste peel of citrus consider a rich source of pharmacologically active metabolites with antioxidant activities.
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Raghavan S, Gurunathan J. Citrus species – a golden treasure box of metabolites that is beneficial against disorders. J Herb Med 2021. [DOI: 10.1016/j.hermed.2021.100438] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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5
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The effects of melatonin prophylaxis on sensory recovery and postoperative pain following orthognathic surgery: a triple-blind randomized controlled trial and biochemical analysis. Int J Oral Maxillofac Surg 2020; 49:446-453. [DOI: 10.1016/j.ijom.2019.07.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 05/21/2019] [Accepted: 07/04/2019] [Indexed: 01/30/2023]
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6
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Dimou C, Karantonis HC, Skalkos D, Koutelidakis AE. Valorization of Fruits by-products to Unconventional Sources of Additives, Oil, Biomolecules and Innovative Functional Foods. Curr Pharm Biotechnol 2020; 20:776-786. [PMID: 30961483 DOI: 10.2174/1389201020666190405181537] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 01/15/2019] [Accepted: 03/21/2019] [Indexed: 02/05/2023]
Abstract
Owning to the increase in the world population as well as the consumer's awareness on the health benefits of consumption of fruits, the demand for both fresh and processed fruits has been increased. The by-product and waste streams generated from fruit processing industries are extremely diverse, owning mainly to different fruits varieties and the wide range of the processes employed towards the production of the end fruit-based products. Due to the increasing production and processing of fruits, disposal of waste and by-product streams has become a serious issue, since these materials are prone to microbial spoilage. Also, the inappropriate waste management practices pose severe environmental issues. Furthermore, the costs of drying and storage of fruit processing residues are economically limiting factors hindering their further exploitation. Therefore, fruit processing by-products such as peels, seeds and unused flesh are often utilized as fertilizers. On the other hand, plant residues contain biomolecules such as vitamins, proteins, minerals, antioxidants and aromatic oil. Recovery of bioactive compounds holds a great potential for their usage in food industry as functional ingredients and nutraceuticals or in pharmaceutical and in cosmetic applications. So, valorization of plant fruit processing by-products to high-value added compounds, constitute a promising alternative not only for addressing fruit residues management issues but also leading to the production of functional food products of high nutritional value, with several potential beneficial health effects. The aim of this paper is to highlight current trends in addressing environmental issues caused by the production of high volumes of specific categories of fruit processing waste streams by investigating their potential usage as natural raw materials for the recovery of valuable bioactive compounds (such as polyphenols, dietary fibers or aromatic oil). The extracted nutrients may be used in the industrial food sector for the production of functional foods, nutraceuticals or even as health promoting natural pharmaceutical ingredients or additives for the production of innovative enriched foods. Highlights: • Fruit processing by product streams are rich in bioactive compounds. • Integration of fruit by-products and waste streams to value added products such as additives, unconventional oil, bioactive compounds and novel functional products is a very interesting approach regarding fruit processing residues exploitation. • Recovering of biomolecules from fruit residues by non-thermal processes could lead to the efficient production of highly purified functional ingredients. • Negative-valued fruit processing residues could be recycled for the production of health promoting value added products.
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Affiliation(s)
- Charalampia Dimou
- Department of Food Science and Nutrition, University of the Aegean, Mitropoliti Ioakim 2, Myrina, Lemnos, 81400, Greece
| | - Haralabos C Karantonis
- Department of Food Science and Nutrition, University of the Aegean, Mitropoliti Ioakim 2, Myrina, Lemnos, 81400, Greece
| | - Dimitrios Skalkos
- Department of Food Science and Nutrition, University of the Aegean, Mitropoliti Ioakim 2, Myrina, Lemnos, 81400, Greece
| | - Antonios E Koutelidakis
- Department of Food Science and Nutrition, University of the Aegean, Mitropoliti Ioakim 2, Myrina, Lemnos, 81400, Greece
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7
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Abstract
The authors discuss the concept of atrial myopathy; its relationship to aging, electrophysiological remodeling, and autonomic remodeling; the interplay between atrial myopathy, AF, and stroke; and suggest how to identify patients with atrial myopathy and how to incorporate atrial myopathy into decisions about anticoagulation. Atrial myopathy seen in animal models of AF and in patients with AF is the result of a combination of factors that lead to electrical and structural remodeling in the atrium. Although AF may lead to the initiation and/or progression of this myopathy, the presence of AF is by no means essential to the development or the maintenance of the atrial myopathic state. Methods to identify atrial myopathy include atrial electrograms, tissue biopsy, cardiac imaging, and certain serum biomarkers. A promising modality is 4-dimensional flow cardiac magnetic resonance. The concept of atrial myopathy may help guide oral anticoagulant therapy in selected groups of patients with AF, particularly those with low to intermediate risk of strokes and those who have undergone successful AF ablation. This review highlights the need for prospective randomized trials to test these hypotheses.
This paper discusses the evolving concept of atrial myopathy by presenting how it develops and how it affects the properties of the atria. It also reviews the complex relationships among atrial myopathy, atrial fibrillation (AF), and stroke. Finally, it discusses how to apply the concept of atrial myopathy in the clinical setting—to identify patients with atrial myopathy and to be more selective in anticoagulation in a subset of patients with AF. An apparent lack of a temporal relationship between episodes of paroxysmal AF and stroke in patients with cardiac implantable electronic devices has led investigators to search for additional factors that are responsible for AF-related strokes. Multiple animal models and human studies have revealed a close interplay of atrial myopathy, AF, and stroke via various mechanisms (e.g., aging, inflammation, oxidative stress, and stretch), which, in turn, lead to fibrosis, electrical and autonomic remodeling, and a pro-thrombotic state. The complex interplay among these mechanisms creates a vicious cycle of ever-worsening atrial myopathy and a higher risk of more sustained AF and strokes. By highlighting the importance of atrial myopathy and the risk of strokes independent of AF, this paper reviews the methods to identify patients with atrial myopathy and proposes a way to incorporate the concept of atrial myopathy to guide anticoagulation in patients with AF.
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Key Words
- 4D, 4 dimensional
- AF, atrial fibrillation
- APD, action potential duration
- CMR, cardiac magnetic resonance
- CRP, C-reactive protein
- Ca2+, calcium
- Cx, connexin
- GDF, growth differentiation factor
- IL, interleukin
- K+, potassium
- LA, left atrial
- LAA, left atrial appendage
- NADPH, nicotinamide adenine dinucleotide phosphate
- NOX2, catalytic, membrane-bound subunit of NADPH oxidase
- NT-proBNP, N-terminal pro B-type natriuretic peptide
- OAC, oral anticoagulant
- ROS, reactive oxygen species
- TGF, transforming growth factor
- TNF, tumor necrosis factor
- atrial fibrillation
- atrial myopathy
- electrophysiology
- thrombosis
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Affiliation(s)
- Mark J Shen
- Feinberg Cardiovascular and Renal Research Institute, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.,Cardiac Electrophysiology, Prairie Heart Institute of Illinois, HSHS St. John's Hospital, Springfield, Illinois
| | - Rishi Arora
- Feinberg Cardiovascular and Renal Research Institute, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - José Jalife
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan.,Centro Nacional de Investigaciones Cardiovasculares, Carlos III (CNIC), and CIBERCV, Madrid, Spain
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8
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Li S, Fujino M, Takahara T, Li XK. Protective role of heme oxygenase-1 in fatty liver ischemia-reperfusion injury. Med Mol Morphol 2019; 52:61-72. [PMID: 30171344 PMCID: PMC6542780 DOI: 10.1007/s00795-018-0205-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 08/21/2018] [Indexed: 12/12/2022]
Abstract
Ischemia-reperfusion (IR) injury is a kind of injury resulting from the restoration of the blood supply after blood vessel closure during liver transplantation and is the main cause of graft failure. The pathophysiological mechanisms of hepatic IR include a variety of oxidative stress responses. Hepatic IR is characterized by ischemia and hypoxia inducing oxidative stress, immune response and apoptosis. Fat-denatured livers are also used as donors due to the lack of liver donors. Fatty liver is less tolerant to IR than normal liver. Heme oxygenase (HO) is an enzyme that breaks down hemoglobin to bilirubin, ferrous iron and carbon monoxide (CO). Inducible HO subtype HO-1 is an important protective molecule in mammalian cells used to improve acute and chronic liver injury owing to its characteristic anti-inflammatory and anti-apoptotic qualities. HO-1 degrades heme, and its reaction product CO has been shown to reduce hepatic IR injury and increase the survival rate of grafts. As an induced form of HO, HO-1 also exerts a protective effect against liver IR injury and may be useful as a new strategy of ameliorating this kind of damage. This review summarizes the protective effects of HO-1 in liver IR injury, especially in fatty liver.
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Affiliation(s)
- Shaowei Li
- Division of Transplantation Immunology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan
| | - Masayuki Fujino
- Division of Transplantation Immunology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Terumi Takahara
- Third Department of Internal Medicine, University of Toyama, Toyama, Japan
| | - Xiao-Kang Li
- Division of Transplantation Immunology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan.
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9
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Yoo S, Aistrup G, Shiferaw Y, Ng J, Mohler PJ, Hund TJ, Waugh T, Browne S, Gussak G, Gilani M, Knight BP, Passman R, Goldberger JJ, Wasserstrom JA, Arora R. Oxidative stress creates a unique, CaMKII-mediated substrate for atrial fibrillation in heart failure. JCI Insight 2018; 3:120728. [PMID: 30385719 DOI: 10.1172/jci.insight.120728] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 09/27/2018] [Indexed: 12/31/2022] Open
Abstract
The precise mechanisms by which oxidative stress (OS) causes atrial fibrillation (AF) are not known. Since AF frequently originates in the posterior left atrium (PLA), we hypothesized that OS, via calmodulin-dependent protein kinase II (CaMKII) signaling, creates a fertile substrate in the PLA for triggered activity and reentry. In a canine heart failure (HF) model, OS generation and oxidized-CaMKII-induced (Ox-CaMKII-induced) RyR2 and Nav1.5 signaling were increased preferentially in the PLA (compared with left atrial appendage). Triggered Ca2+ waves (TCWs) in HF PLA myocytes were particularly sensitive to acute ROS inhibition. Computational modeling confirmed a direct relationship between OS/CaMKII signaling and TCW generation. CaMKII phosphorylated Nav1.5 (CaMKII-p-Nav1.5 [S571]) was located preferentially at the intercalated disc (ID), being nearly absent at the lateral membrane. Furthermore, a decrease in ankyrin-G (AnkG) in HF led to patchy dropout of CaMKII-p-Nav1.5 at the ID, causing its distribution to become spatially heterogeneous; this corresponded to preferential slowing and inhomogeneity of conduction noted in the HF PLA. Computational modeling illustrated how conduction slowing (e.g., due to increase in CaMKII-p-Nav1.5) interacts with fibrosis to cause reentry in the PLA. We conclude that OS via CaMKII leads to substrate for triggered activity and reentry in HF PLA by mechanisms independent of but complementary to fibrosis.
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Affiliation(s)
- Shin Yoo
- Feinberg Cardiovascular Research and Renal Institute, Northwestern University-Feinberg School of Medicine, Chicago, Illinois, USA
| | - Gary Aistrup
- Feinberg Cardiovascular Research and Renal Institute, Northwestern University-Feinberg School of Medicine, Chicago, Illinois, USA
| | - Yohannes Shiferaw
- Department of Physics, California State University, Northridge, California, USA
| | - Jason Ng
- Feinberg Cardiovascular Research and Renal Institute, Northwestern University-Feinberg School of Medicine, Chicago, Illinois, USA
| | - Peter J Mohler
- Dorothy M. Davis Heart and Lung Research Institute, Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Thomas J Hund
- Dorothy M. Davis Heart and Lung Research Institute, Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Trent Waugh
- Feinberg Cardiovascular Research and Renal Institute, Northwestern University-Feinberg School of Medicine, Chicago, Illinois, USA
| | - Suzanne Browne
- Feinberg Cardiovascular Research and Renal Institute, Northwestern University-Feinberg School of Medicine, Chicago, Illinois, USA
| | - Georg Gussak
- Feinberg Cardiovascular Research and Renal Institute, Northwestern University-Feinberg School of Medicine, Chicago, Illinois, USA
| | - Mehul Gilani
- Feinberg Cardiovascular Research and Renal Institute, Northwestern University-Feinberg School of Medicine, Chicago, Illinois, USA
| | - Bradley P Knight
- Feinberg Cardiovascular Research and Renal Institute, Northwestern University-Feinberg School of Medicine, Chicago, Illinois, USA
| | - Rod Passman
- Feinberg Cardiovascular Research and Renal Institute, Northwestern University-Feinberg School of Medicine, Chicago, Illinois, USA
| | - Jeffrey J Goldberger
- Feinberg Cardiovascular Research and Renal Institute, Northwestern University-Feinberg School of Medicine, Chicago, Illinois, USA
| | - J Andrew Wasserstrom
- Feinberg Cardiovascular Research and Renal Institute, Northwestern University-Feinberg School of Medicine, Chicago, Illinois, USA
| | - Rishi Arora
- Feinberg Cardiovascular Research and Renal Institute, Northwestern University-Feinberg School of Medicine, Chicago, Illinois, USA
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10
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Molecular hydrogen protects against ischemia-reperfusion injury in a mouse fatty liver model via regulating HO-1 and Sirt1 expression. Sci Rep 2018; 8:14019. [PMID: 30232347 PMCID: PMC6145907 DOI: 10.1038/s41598-018-32411-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 08/23/2018] [Indexed: 12/19/2022] Open
Abstract
Fatty liver has lower tolerance against ischemia-reperfusion (I/R) injury in liver operations, including liver transplantation. Seeking to ameliorate liver injury following I/R in fatty liver, we examined the protective effect of hydrogen (H2) saline on I/R liver injury in a methionine and choline-deficient plus high fat (MCDHF) diet-induced fatty liver mouse model. Saline containing 7 ppm H2 was administrated during the process of I/R. Livers were obtained and analyzed. Primary hepatocytes and Kupffer cells (KCs) were obtained from fatty liver and subjected to hypoxia/reoxygenation. Apoptosis-related proteins and components of the signaling pathway were analyzed after treatment with hydrogen gas. The MCDHF I/R group showed higher levels of AST and ALT in serum, TUNEL-positive apoptotic cells, F4/80 immunopositive cells, mRNA levels of inflammatory cytokines, constituents of the signaling pathway, pro-apoptotic molecules in liver, and KCs and/or primary hepatocytes, compared to the control group. In contrast, H2 treatment significantly suppressed the signs of I/R injury in fatty liver. Moreover, the expression of Bcl-2, HO-1, and Sirt1 in liver, KCs, and hepatocytes by hydrogen gas were increased, whereas caspase activation, Bax, and acetylation of p53 were suppressed by hydrogen gas. These results demonstrated that H2 treatment ameliorated I/R liver injury in a fatty liver model by reducing hepatocyte apoptosis, inhibiting macrophage activation and inflammatory cytokines, and inducing HO-1 and Sirt1 expression. Taken togather, treatment with H2 saline may have a protective effect and safe therapeutic activity during I/R events, such as in liver transplantation with fatty liver.
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11
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Formanowicz D, Radom M, Rybarczyk A, Formanowicz P. The role of Fenton reaction in ROS-induced toxicity underlying atherosclerosis – modeled and analyzed using a Petri net-based approach. Biosystems 2018; 165:71-87. [DOI: 10.1016/j.biosystems.2018.01.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 01/02/2018] [Accepted: 01/04/2018] [Indexed: 12/12/2022]
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12
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Muralidharan P, Cserne Szappanos H, Ingley E, Hool LC. The cardiac L-type calcium channel alpha subunit is a target for direct redox modification during oxidative stress-the role of cysteine residues in the alpha interacting domain. Clin Exp Pharmacol Physiol 2017; 44 Suppl 1:46-54. [PMID: 28306174 DOI: 10.1111/1440-1681.12750] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 02/16/2017] [Accepted: 03/07/2017] [Indexed: 01/21/2023]
Abstract
Cardiovascular disease is the leading cause of death in the Western world. The incidence of cardiovascular disease is predicted to further rise with the increase in obesity and diabetes and with the aging population. Even though the survival rate from ischaemic heart disease has improved over the past 30 years, many patients progress to a chronic pathological condition, known as cardiac hypertrophy that is associated with an increase in morbidity and mortality. Reactive oxygen species (ROS) and calcium play an essential role in mediating cardiac hypertrophy. The L-type calcium channel is the main route for calcium influx into cardiac myocytes. There is now good evidence for a direct role for the L-type calcium channel in the development of cardiac hypertrophy. Cysteines on the channel are targets for redox modification and glutathionylation of the channel can modulate the function of the channel protein leading to the onset of pathology. The cysteine responsible for modification of L-type calcium channel function has now been identified. Detailed understanding of the role of cysteines as possible targets during oxidative stress may assist in designing therapy to prevent the development of hypertrophy and heart failure.
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Affiliation(s)
- Padmapriya Muralidharan
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, WA, Australia
| | - Henrietta Cserne Szappanos
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, WA, Australia
| | - Evan Ingley
- Harry Perkins Institute of Medical Research and Centre for Medical Research, University of Western Australia, Perth, WA, Australia.,School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA, Australia
| | - Livia C Hool
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, WA, Australia.,Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
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13
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Lee HI, Park BR, Chun SW. Reactive oxygen species increase neuronal excitability via activation of nonspecific cation channel in rat medullary dorsal horn neurons. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2017; 21:371-376. [PMID: 28706450 PMCID: PMC5507775 DOI: 10.4196/kjpp.2017.21.4.371] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 03/10/2017] [Accepted: 03/20/2017] [Indexed: 02/07/2023]
Abstract
The caudal subnucleus of the spinal trigeminal nucleus (medullary dorsal horn; MDH) receives direct inputs from small diameter primary afferent fibers that predominantly transmit nociceptive information in the orofacial region. Recent studies indicate that reactive oxygen species (ROS) is involved in persistent pain, primarily through spinal mechanisms. In this study, we aimed to investigate the role of xanthine/xanthine oxidase (X/XO) system, a known generator of superoxide anion (O2·−), on membrane excitability in the rat MDH neurons. For this, we used patch clamp recording and confocal imaging. An application of X/XO (300 µM/30 mU) induced membrane depolarization and inward currents. When slices were pretreated with ROS scavengers, such as phenyl N-tert-butylnitrone (PBN), superoxide dismutase (SOD), and catalase, X/XO-induced responses decreased. Fluorescence intensity in the DCF-DA and DHE-loaded MDH cells increased on the application of X/XO. An anion channel blocker, 4,4-diisothiocyanatostilbene-2,2-disulfonic acid (DIDS), significantly decreased X/XO-induced depolarization. X/XO elicited an inward current associated with a linear current-voltage relationship that reversed near −40 mV. X/XO-induced depolarization reduced in the presence of La3+, a nonselective cation channel (NSCC) blocker, and by lowering the external sodium concentration, indicating that membrane depolarization and inward current are induced by influx of Na+ ions. In conclusion, X/XO-induced ROS modulate the membrane excitability of MDH neurons, which was related to the activation of NSCC.
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Affiliation(s)
- Hae In Lee
- Department of Dental Hygiene, Gwangyang Health Science University, Gwangyang 57764, Korea
| | - Byung Rim Park
- Department of Physiology, College of Medicine, Wonkwang University, Iksan 54538, Korea
| | - Sang Woo Chun
- Department of Oral Physiology, College of Dentistry, Wonkwang University, Iksan 54538, Korea
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14
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Beharry KD, Cai CL, Valencia GB, Valencia AM, Lazzaro DR, Bany-Mohammed F, Aranda JV. Neonatal Intermittent Hypoxia, Reactive Oxygen Species, and Oxygen-Induced Retinopathy. REACTIVE OXYGEN SPECIES (APEX, N.C.) 2017; 3:12-25. [PMID: 29951586 DOI: 10.20455/ros.2017.805] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Most of the major morbidities in the preterm newborn are caused by or are associated with oxygen-induced injuries and are aptly called "oxygen radical diseases in neonatology or ORDIN". These include bronchopulmonary dysplasia, retinopathy of prematurity, periventricular leukomalacia, intraventricular hemorrhage, necrotizing enterocolitis and others. Relative hyperoxia immediately after birth, immature antioxidant systems, biomolecular events favoring oxidative stress such as iron availability and the role of hydrogen peroxide as a key molecular mediator of these events are reviewed. Potential therapeutic strategies such as caffeine, antioxidants, non-steroidal anti-inflammatory drugs, and others targeted to these critical sites may help prevent oxidative radical diseases in the newborn resulting in improved neonatal outcomes.
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Affiliation(s)
- Kay D Beharry
- Department of Pediatrics, Division of Neonatal-Perinatal Medicine, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA.,Department of Ophthalmology, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA.,State University of New York Eye Institute, New York, NY 10075, USA
| | - Charles L Cai
- Department of Pediatrics, Division of Neonatal-Perinatal Medicine, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Gloria B Valencia
- Department of Pediatrics, Division of Neonatal-Perinatal Medicine, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Arwin M Valencia
- Department of Pediatrics, Division of Neonatal-Perinatal Medicine, Summerlin Hospital Medical Center, Valley Healthcare System, Las Vegas, NV 89135, USA
| | - Douglas R Lazzaro
- Department of Ophthalmology, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA.,State University of New York Eye Institute, New York, NY 10075, USA
| | - Fayez Bany-Mohammed
- Department of Pediatrics, Division of Neonatal-Perinatal Medicine, University of California, Irvine, CA 92868, USA
| | - Jacob V Aranda
- Department of Pediatrics, Division of Neonatal-Perinatal Medicine, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA.,Department of Ophthalmology, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA.,State University of New York Eye Institute, New York, NY 10075, USA
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Jovanovic ZD, Stanojevic MB, Nedeljkov VB. The neurotoxic effects of hydrogen peroxide and copper in Retzius nerve cells of the leech Haemopis sanguisuga. Biol Open 2016; 5:381-8. [PMID: 26935393 PMCID: PMC4890660 DOI: 10.1242/bio.014936] [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] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Oxidative stress and the generation of reactive oxygen species (ROS) play an important role in cellular damage. Electrophysiological analyses have shown that membrane transport proteins are susceptible to ROS. In the present study, oxidative stress was induced in Retzius nerve cells of the leechHaemopis sanguisugaby bath application of 1 mM of hydrogen peroxide (H2O2) and 0.02 mM of copper (Cu) for 20 min. The H2O2/Cu(II) produced considerable changes in the electrical properties of the Retzius nerve cells. Intracellular recording of the resting membrane potential revealed that the neuronal membrane was depolarized in the presence of H2O2/Cu(II). We found that the amplitude of action potentials decreased, while the duration augmented in a progressive way along the drug exposure time. The combined application of H2O2and Cu(II) caused an initial excitation followed by depression of the spontaneous electrical activity. Voltage-clamp recordings revealed a second effect of the oxidant, a powerful inhibition of the outward potassium channels responsible for the repolarization of action potentials. The neurotoxic effect of H2O2/Cu(II) on the spontaneous spike electrogenesis and outward K(+)current of Retzius nerve cells was reduced in the presence of hydroxyl radical scavengers, dimethylthiourea and dimethyl sulfoxide, but not mannitol. This study provides evidence for the oxidative modification of outward potassium channels in Retzius nerve cells. The oxidative mechanism of the H2O2/Cu(II) system action on the electrical properties of Retzius neurons proposed in this study might have a wider significance, referring not only to leeches but also to mammalian neurons.
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Affiliation(s)
- Zorica D Jovanovic
- Department of Pathological Physiology, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia
| | - Marija B Stanojevic
- Institute for Pathological Physiology, School of Medicine, University of Belgrade, 11000 Belgrade, Serbia
| | - Vladimir B Nedeljkov
- Institute for Pathological Physiology, School of Medicine, University of Belgrade, 11000 Belgrade, Serbia
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Pardillo-Díaz R, Carrascal L, Muñoz MF, Ayala A, Nunez-Abades P. Time and dose dependent effects of oxidative stress induced by cumene hydroperoxide in neuronal excitability of rat motor cortex neurons. Neurotoxicology 2016; 53:201-214. [PMID: 26877221 DOI: 10.1016/j.neuro.2016.02.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 01/22/2016] [Accepted: 02/09/2016] [Indexed: 12/19/2022]
Abstract
It has been claimed that oxidative stress and the production of reactive oxygen radicals can contribute to neuron degeneration and might be one factor in the development of different neurological diseases. In our study, we have attempted to clarify how oxidative damage induces dose dependent changes in functional membrane properties of neurons by means of whole cell patch clamp techniques in brain slices from young adult rats. Our research demonstrates physiological changes in membrane properties of pyramidal motor cortex neurons exposed to 3 concentrations of cumene hydroperoxide (CH; 1, 10 and 100μM) during 30min. Results show that oxidative stress induced by CH evokes important changes, in a concentration and time dependent manner, in the neuronal excitability of motor cortex neurons of the rat: (i) Low concentration of the drug (1μM) already blocks inward rectifications (sag) and decreases action potential amplitude and gain, a drug concentration which has no effects on other neuronal populations, (ii) 10μM of CH depresses the excitability of pyramidal motor cortex neurons by decreasing input resistance, amplitude of the action potential, and gain and maximum frequency of the repetitive firing discharge, and (iii) 100μM completely blocks the capability to produce repetitive discharge of action potentials in all cells. Both larger drug concentrations and/or longer times of exposure to CH narrow the current working range. This happens because of the increase in the rheobase, and the reduction of the cancelation current. The effects caused by oxidative stress, including those produced by the level of lipid peroxidation, are practically irreversible and, this, therefore, indicates that neuroprotective agents should be administered at the first symptoms of alterations to membrane properties. In fact, the pre-treatment with melatonin, acting as an antioxidant, prevented the lipid peroxidation and the physiological changes induced by CH. Larger cells (as estimated by their cell capacitance) were also more susceptible to oxidative stress. Our results provide previously unavailable observations that large size and high sensitivity to oxidative stress (even at low concentrations) make pyramidal neurons of the motor cortex, in particular corticofugal neurons, more susceptible to cell death when compared with other neuronal populations. These results could also shed some light on explaining the causes behind diseases such as Amyotrophic Lateral Sclerosis.
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Affiliation(s)
- R Pardillo-Díaz
- Department of Physiology, School of Pharmacy, University of Seville, Spain
| | - L Carrascal
- Department of Physiology, School of Pharmacy, University of Seville, Spain
| | - M F Muñoz
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Seville, Spain
| | - A Ayala
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Seville, Spain
| | - P Nunez-Abades
- Department of Physiology, School of Pharmacy, University of Seville, Spain.
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Chaplin NL, Nieves-Cintrón M, Fresquez AM, Navedo MF, Amberg GC. Arterial Smooth Muscle Mitochondria Amplify Hydrogen Peroxide Microdomains Functionally Coupled to L-Type Calcium Channels. Circ Res 2015; 117:1013-23. [PMID: 26390880 DOI: 10.1161/circresaha.115.306996] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/18/2015] [Indexed: 01/21/2023]
Abstract
RATIONALE Mitochondria are key integrators of convergent intracellular signaling pathways. Two important second messengers modulated by mitochondria are calcium and reactive oxygen species. To date, coherent mechanisms describing mitochondrial integration of calcium and oxidative signaling in arterial smooth muscle are incomplete. OBJECTIVE To address and add clarity to this issue, we tested the hypothesis that mitochondria regulate subplasmalemmal calcium and hydrogen peroxide microdomain signaling in cerebral arterial smooth muscle. METHODS AND RESULTS Using an image-based approach, we investigated the impact of mitochondrial regulation of L-type calcium channels on subcellular calcium and reactive oxygen species signaling microdomains in isolated arterial smooth muscle cells. Our single-cell observations were then related experimentally to intact arterial segments and to living animals. We found that subplasmalemmal mitochondrial amplification of hydrogen peroxide microdomain signaling stimulates L-type calcium channels, and that this mechanism strongly impacts the functional capacity of the vasoconstrictor angiotensin II. Importantly, we also found that disrupting this mitochondrial amplification mechanism in vivo normalized arterial function and attenuated the hypertensive response to systemic endothelial dysfunction. CONCLUSIONS From these observations, we conclude that mitochondrial amplification of subplasmalemmal calcium and hydrogen peroxide microdomain signaling is a fundamental mechanism regulating arterial smooth muscle function. As the principle components involved are fairly ubiquitous and positioning of mitochondria near the plasma membrane is not restricted to arterial smooth muscle, this mechanism could occur in many cell types and contribute to pathological elevations of intracellular calcium and increased oxidative stress associated with many diseases.
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Affiliation(s)
- Nathan L Chaplin
- From the Department of Biomedical Sciences, Colorado State University, Fort Collins (N.L.C., A.M.F., G.C.A.); and Department of Pharmacology, University of California, Davis (M.N.-C., M.F.N.)
| | - Madeline Nieves-Cintrón
- From the Department of Biomedical Sciences, Colorado State University, Fort Collins (N.L.C., A.M.F., G.C.A.); and Department of Pharmacology, University of California, Davis (M.N.-C., M.F.N.)
| | - Adriana M Fresquez
- From the Department of Biomedical Sciences, Colorado State University, Fort Collins (N.L.C., A.M.F., G.C.A.); and Department of Pharmacology, University of California, Davis (M.N.-C., M.F.N.)
| | - Manuel F Navedo
- From the Department of Biomedical Sciences, Colorado State University, Fort Collins (N.L.C., A.M.F., G.C.A.); and Department of Pharmacology, University of California, Davis (M.N.-C., M.F.N.)
| | - Gregory C Amberg
- From the Department of Biomedical Sciences, Colorado State University, Fort Collins (N.L.C., A.M.F., G.C.A.); and Department of Pharmacology, University of California, Davis (M.N.-C., M.F.N.).
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Viola HM, Hool LC. Role of the cytoskeleton in communication between L-type Ca(2+) channels and mitochondria. Clin Exp Pharmacol Physiol 2015; 40:295-304. [PMID: 23551128 DOI: 10.1111/1440-1681.12072] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 02/25/2013] [Accepted: 02/26/2013] [Indexed: 12/15/2022]
Abstract
The L-type Ca(2+) channel is the main route for Ca(2+) entry into cardiac myocytes, which is essential for the maintenance of cardiac excitation and contraction. Alterations in L-type Ca(2+) channel activity and Ca(2+) homeostasis have been implicated in the development of cardiomyopathies. Cardiac excitation and contraction is fuelled by ATP, synthesized predominantly by the mitochondria via the Ca(2+)-dependent process oxidative phosphorylation. Mitochondrial reactive oxygen species (ROS) are by-products of oxidative phosphorylation and are associated with the development of cardiac pathology. The cytoskeleton plays a role in the communication of signals from the plasma membrane to intracellular organelles. There is good evidence that both L-type Ca(2+) channel activity and mitochondrial function can be modulated by changes in the cytoskeletal network. Activation of the L-type Ca(2+) channel can regulate mitochondrial function through cytoskeletal proteins as a result of transmission of movement from the β(2)-subunit of the channel that occurs during activation and inactivation of the channel. An association between cytoskeletal proteins and the mitochondrial voltage-dependent anion channel (VDAC) may play a role in this response. The L-type Ca(2+) channel is the initiator of contraction in cardiac muscle and the VDAC is responsible for regulating mitochondrial ATP/ADP trafficking. This article presents evidence that a functional coupling between L-type Ca(2+) channels and mitochondria may assist in meeting myocardial energy demand on a beat-to-beat basis.
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Affiliation(s)
- Helena M Viola
- Cardiovascular Electrophysiology Laboratory, School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, WA, Australia
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Oxidative stress induced by cumene hydroperoxide evokes changes in neuronal excitability of rat motor cortex neurons. Neuroscience 2015; 289:85-98. [PMID: 25592424 DOI: 10.1016/j.neuroscience.2014.12.055] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 12/30/2014] [Accepted: 12/31/2014] [Indexed: 01/12/2023]
Abstract
Oxidative stress and the production of reactive oxygen radicals play a key role in neuronal cell damage. This paper describes an in vitro study that explores the neuronal responses to oxidative stress focusing on changes in neuronal excitability and functional membrane properties. This study was carried out in pyramidal cells of the motor cortex by applying whole-cell patch-clamp techniques on brain slices from young adult rats. Oxygen-derived free radical formation was induced by bath application of 10μM cumene hydroperoxide (CH) for 30min. CH produced marked changes in the electrophysiological properties of neurons (n=30). Resting membrane potential became progressively depolarized, as well as depolarization voltage, with no variations in voltage threshold. Membrane resistance showed a biphasic behavior, increasing after 5min of drug exposure and then it started to decrease, even under control values, after 15 and 30min. At the same time, changes in membrane resistance produced compensatory variations in the rheobase. The amplitude of the action potentials diminished and the duration increased progressively over time. Some of the neurons under study also lost their ability to discharge action potentials in a repetitive way. Most of the neurons, however, kept their repetitive discharge even though their maximum frequency and gain decreased. Furthermore, cancelation of the repetitive firing discharge took place at intensities that decreased with time of exposure to CH, which resulted in a narrower working range. We can conclude that oxidative stress compromises both neuronal excitability and the capability of generating action potentials, and so this type of neuronal functional failure could precede the neuronal death characteristics of many neurodegenerative diseases.
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Liu S, Geng B, Zou L, Wei S, Wang W, Deng J, Xu C, Zhao X, Lyu Y, Su X, Xu G. Development of hypertrophic cardiomyopathy in perilipin-1 null mice with adipose tissue dysfunction. Cardiovasc Res 2014; 105:20-30. [DOI: 10.1093/cvr/cvu214] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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Kim SY, Shin KS. Bioactivity of Trifoliate Orange (Poncirus trifoliate) Seed Extracts. Prev Nutr Food Sci 2014; 17:136-40. [PMID: 24471075 PMCID: PMC3866750 DOI: 10.3746/pnf.2012.17.2.136] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 06/13/2012] [Indexed: 11/10/2022] Open
Abstract
Trifoliate orange seed extracts (TSEs) were made using either distilled water (TW), ethanol (TE), or n-hexane (TH), to measure total polyphenol contents, DPPH and ABTS radical scavenging activities, and anti-complementary activity. The results showed that the total polyphenol content showed higher value at TE (235.24 μg/mL, p<0.05) than those of TW (132.65 μg/mL) and TH (165.44 μg/mL) at 10 mg/mL and TE exerted the highest DPPH radical scavenging activity (61.77%, p<0.05), which occurred in the following order: TE>TW (56.87%)>TH (39.78%). The results of ABTS radical scavenging activity showed that TW (34.26%) and TE (31.81%) showed similar activities, which were higher than TH (12.74%, p<0.05). Anti-complementary activity of TE (61% at 500 μg/mL) showed a higher activity when compared with the positive control (60% at 1,000 μg/mL) polysaccharide-K (PSK), a known immuno-active polysaccharide from Coriolus versicolor. Consequently, among TSEs, TE is a byproduct from trifoliate orange and could be an important source of dietary polyphenolic antioxidant compounds and immunopotentiating activity, including complement activation.
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Affiliation(s)
- Seong Yeong Kim
- Nutrition Education, Graduate School of Education, Kyonggi University, Gyeonggi 443-760, Korea
| | - Kwang-Soon Shin
- Department of Food Science and Biotechnology, Kyonggi University, Gyeonggi 443-760, Korea
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22
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Wang Z, Lv H, Song S, Shen X, Yang L, Yu W. Emulsified isoflurane preconditioning protects isolated rat Kupffer cells against hypoxia/reoxygenation-induced injury. Int J Med Sci 2013; 10:286-91. [PMID: 23372435 PMCID: PMC3558717 DOI: 10.7150/ijms.5343] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 01/15/2013] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVE To investigate the protective effect of emulsified isoflurane (EI) preconditioning on isolated rat Kupffer cells (KCs) subjected to hypoxia/reoxygenation (H/R)-induced injury. MATERIALS AND METHODS KCs were isolated by collagenase digestion and purified by Percoll density gradient centrifugation. Primary cultured KCs were divided into five groups: control, H/R plus 0.1% lipid preconditioning, and H/R plus 0.05%, 0.1% or 0.2% emulsified isoflurane preconditioning groups. H/R was induced by 4 h of hypoxia followed by 6 h of reoxygenation. Reactive oxygen species (ROS) production in the KCs and the concentration of tumor necrosis factor-α (TNF-α) in the KC culture media were measured, and the apoptosis of KCs was assayed concomitantly. RESULTS ROS and TNF-α production were markedly induced in the H/R + lipid group, and lower in the 0.2% and 0.1% EI groups (P<0.05). The apoptotic rate in the H/R + lipid group was significantly higher than that in the 0.2% and 0.1% EI groups (P<0.05). CONCLUSIONS Emulsified isoflurane protects isolated rat KCs against H/R induced injury by decreasing the production of ROS and TNF-α and attenuating apoptosis in KCs.
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Affiliation(s)
- Zhenmeng Wang
- Department of Anaesthesia and Intensive Care, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, 200438, China
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23
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JOVANOVIC Z, JOVANOVIC S. A Comparison of the Effects of Cumene Hydroperoxide and Hydrogen Peroxide on Retzius Nerve Cells of the Leech Haemopis sanguisuga. Exp Anim 2013; 62:9-17. [DOI: 10.1538/expanim.62.9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Affiliation(s)
- Zorica JOVANOVIC
- Department of Pathological Physiology, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Svetlana JOVANOVIC
- Clinic of Ophthalmology, Clinical Centre of Kragujevac, Kragujevac, Serbia
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Nishio S, Teshima Y, Takahashi N, Thuc LC, Saito S, Fukui A, Kume O, Fukunaga N, Hara M, Nakagawa M, Saikawa T. Activation of CaMKII as a key regulator of reactive oxygen species production in diabetic rat heart. J Mol Cell Cardiol 2012; 52:1103-11. [DOI: 10.1016/j.yjmcc.2012.02.006] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 02/15/2012] [Accepted: 02/18/2012] [Indexed: 12/30/2022]
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25
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Kamga C, Krishnamurthy S, Shiva S. Myoglobin and mitochondria: a relationship bound by oxygen and nitric oxide. Nitric Oxide 2012; 26:251-8. [PMID: 22465476 DOI: 10.1016/j.niox.2012.03.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 03/22/2012] [Indexed: 01/04/2023]
Abstract
Since their initial discovery over a century ago, our knowledge of the functions of myoglobin and the mitochondrion has gradually evolved. The mitochondrion, once thought to be solely responsible for energy production, is now known to be an integral redox and apoptotic signal transducer within the cell. Likewise, myoglobin, traditionally thought of only as an oxygen store, has emerged as a physiological catalyst that can modulate reactive oxygen species levels, facilitate oxygen diffusion and scavenge or generate nitric oxide (NO) depending on oxygen tensions within the cell. By virtue of its unique ability to regulate O(2) and NO levels within the cell, myoglobin can modulate mitochondrial function in energy-demanding tissues such as the beating heart and exercising muscle. In this review, we present the conventional functions of myoglobin and mitochondria, and describe how these roles have been reassessed and advanced, particularly in the context of NO and nitrite signaling. We present the mechanisms by which mitochondria and myoglobin regulate one another within the cell through their interactions with NO and oxygen and discuss the implications of these interactions in terms of health and disease.
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Affiliation(s)
- Christelle Kamga
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, United States
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26
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Sachdeva J, Tanwar V, Golechha M, Siddiqui KM, Nag TC, Ray R, Kumari S, Arya DS. Crocus sativus L. (saffron) attenuates isoproterenol-induced myocardial injury via preserving cardiac functions and strengthening antioxidant defense system. ACTA ACUST UNITED AC 2010; 64:557-64. [PMID: 21144717 DOI: 10.1016/j.etp.2010.11.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 10/28/2010] [Accepted: 11/15/2010] [Indexed: 11/16/2022]
Abstract
Saffron (dried stigmas of Crocus sativus L.), a naturally derived plant product, has long been used as a traditional ancient medicine against various human diseases. The aim of the series of experiments was to systematically determine whether saffron exerts cardioprotection in isoproterenol-induced myocardial damage. Male Wistar rats (150-175 g) were divided into five groups: control, isoproterenol (ISO) and three saffron (200, 400 and 800 mg/kg) treatment groups. Aqueous extract of saffron or vehicle was administered orally to rats for four weeks. On days 28 and 29, the animals in ISO and saffron treatment groups were administered ISO (85 mg/kg, s.c.) at an interval of 24 h. On day 30, after recording hemodynamics and left ventricular functions, animals were sacrificed for biochemical, histopathological and electromicroscopical examinations. Isoproterenol challenged animals showed depressed hemodynamics and left ventricular functions as evident by decreased left ventricular rate of peak positive and negative pressure change and elevated left ventricular end-diastolic pressure. Structural and ultrastructural studies further confirmed the damage which was reconfirmed by increased thiobarbituric acid reactive substances (p<0.001) and decreased creatine kinase-MB and lactate dehydrogenase (p<0.001). In addition, significant reduction in superoxide dismutase and catalase (p<0.001) was observed in ISO group. Our results suggested that saffron at all the doses exerted significant cardioprotective effect by preserving hemodynamics and left ventricular functions, maintaining structural integrity and augmenting antioxidant status. Among the different doses used, saffron at 400mg/kg dose exhibited maximum protective effects which could be due to maintenance of the redox status of the cell reinforcing its role as an antioxidant.
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Affiliation(s)
- Jaspreet Sachdeva
- Cardiovascular Laboratory, Department of Pharmacology, All India Institute of Medical Sciences, New Delhi 110029, India
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Heusch P, Canton M, Aker S, van de Sand A, Konietzka I, Rassaf T, Menazza S, Brodde OE, Di Lisa F, Heusch G, Schulz R. The contribution of reactive oxygen species and p38 mitogen-activated protein kinase to myofilament oxidation and progression of heart failure in rabbits. Br J Pharmacol 2010; 160:1408-16. [PMID: 20590631 DOI: 10.1111/j.1476-5381.2010.00793.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE The formation of reactive oxygen species (ROS) is increased in heart failure (HF). However, the causal and mechanistic relationship of ROS formation with contractile dysfunction is not clear in detail. Therefore, ROS formation, myofibrillar protein oxidation and p38 MAP kinase activation were related to contractile function in failing rabbit hearts. EXPERIMENTAL APPROACH AND KEY RESULTS Three weeks of rapid left ventricular (LV) pacing reduced LV shortening fraction (SF, echocardiography) from 32 +/- 1% to 13 +/- 1%. ROS formation, as assessed by dihydroethidine staining, increased by 36 +/- 8% and was associated with increased tropomyosin oxidation, as reflected by dimer formation (dimer to monomer ratio increased 2.28 +/- 0.66-fold in HF vs. sham, P < 0.05). Apoptosis (TdT-mediated dUTP nick end labelling staining) increased more than 12-fold after 3 weeks of pacing when a significant increase in the phosphorylation of p38 MAP kinase and HSP27 was detected (Western blotting). Vitamins C and E abolished the increases in ROS formation and tropomyosin oxidation along with an improvement of LVSF (19 +/- 1%, P < 0.05 vs. untreated HF) and prevention of apoptosis, but without modifying p38 MAP kinase activation. Inhibition of p38 MAP kinase by SB281832 counteracted ROS formation, tropomyosin oxidation and contractile failure, without affecting apoptosis. CONCLUSIONS AND IMPLICATIONS Thus, p38 MAP kinase activation appears to be upstream rather than downstream of ROS, which impacts on LV function through myofibrillar oxidation. p38 MAP kinase inhibition is a potential target to prevent or treat HF.
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Affiliation(s)
- P Heusch
- Institute of Pathophysiology, University of Essen Medical School, Essen, Germany
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28
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Thuc LC, Teshima Y, Takahashi N, Nagano-Torigoe Y, Ezaki K, Yufu K, Nakagawa M, Hara M, Saikawa T. Mitochondrial K(ATP) channels-derived reactive oxygen species activate pro-survival pathway in pravastatin-induced cardioprotection. Apoptosis 2010; 15:669-78. [PMID: 20151195 DOI: 10.1007/s10495-010-0473-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Reactive oxygen species (ROS) are important intracellular signaling molecules and are implicated in cardioprotective pathways including ischemic preconditioning. Statins have been shown to have cardioprotective effects against ischemia/reperfusion injury, however, the precise mechanisms remain to be elucidated. We hypothesized that ROS-mediated signaling cascade may be involved in pravastatin-induced cardioprotection. Cultured rat cardiomyocytes were exposed to H(2)O(2) for 30 min to induce cell injury. Pravastatin significantly suppressed H(2)O(2)-induced cell death evaluated by propidium iodide staining and the MTT assay. Incubation with pravastatin activated catalase, and prevented a ROS burst induced by H(2)O(2), which preserved mitochondrial membrane potential. Protective effects were induced very rapidly within 10 min, which was concordant with the up-regulation of phosphorylated ERK1/2. L-NAME, 5HD, N-acetylcysteine (NAC) and staurosporine inhibited ERK1/2 phosphorylation and also reduced pravastatin-induced cardioprotection, suggesting NO, mitochondrial K(ATP) (mitoK(ATP)) channels, ROS and PKC should be involved in the cardioprotective signaling. We also demonstrated that pravastatin moderately up-regulated ROS generation in a 5HD-inhibitable manner. In isolated perfused rat heart experiments, pravastatin administered 10 min prior to no-flow global ischemia significantly improved left ventricular functional recovery, and also reduced infarct size, which were attenuated by the treatment with NAC, 5HD, L-NAME or staurosporine. Administration of pravastatin from the beginning of reperfusion also conferred cardioprotection. Pravastatin protected the cardiomyocytes against oxidative stress by preventing the ROS burst and preserving mitochondrial function. Moderately up-regulated ROS production by mitoK(ATP) channels opening is involved in the pro-survival signaling cascade activated by pravastatin.
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Affiliation(s)
- Luong Cong Thuc
- Department of Laboratory Examination and Diagnostics, Oita University, Yufu-city, Japan
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Kaplan P, Tatarkova Z, Engler I, Calkovska A, Mokra D, Drgova A, Kovalska M, Lehotsky J, Dobrota D. Effects of long-term oxygen treatment on alpha-ketoglutarate dehydrogenase activity and oxidative modifications in mitochondria of the guinea pig heart. Eur J Med Res 2010; 14 Suppl 4:116-20. [PMID: 20156740 PMCID: PMC3521383 DOI: 10.1186/2047-783x-14-s4-116] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE Oxygen therapy is used for the treatment of various diseases, but prolonged exposure to high concentrations of O(2) is also associated with formation of free radicals and oxidative damage. METHODS In the present study we compared alpha-ketoglutarate dehydrogenase (KGDH) activity and mitochondrial oxidative damage in the hearts of guinea pigs after long-term (17 and 60 h) oxygenation with 100% normobaric O(2) and with partially negatively (O(2 neg)) or positively (O(2 posit)) ionized oxygen. RESULTS Inhalation of O(2) led to significant loss in KGDH activity and thiol group content and accumulation of bityrosines. Inhalation of O(2 neg) was accompanied by more pronounced KGDH inhibition, possibly due to additional formation of protein-lipid conjugates. In contrast, O(2 posit) prevented loss in KGDH activity and diminished mitochondrial oxidative damage. CONCLUSIONS These findings suggest that oxygen treatment is associated with impairment of heart energy metabolism and support the view that inhalation of O(2 posit) optimizes the beneficial effects of oxygen therapy.
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Affiliation(s)
- Peter Kaplan
- Department of Medical Biochemistry, Center of Excellence for Cardiovacular Research of the Slovak Academy of Sciences, Jessenius Faculty of Medicine, Comenius University, Martin, Slovakia.
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30
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High-glucose condition reduces cardioprotective effects of insulin against mechanical stress-induced cell injury. Life Sci 2010; 87:154-61. [DOI: 10.1016/j.lfs.2010.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 05/25/2010] [Accepted: 06/05/2010] [Indexed: 11/18/2022]
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Dyavanapalli J, Rimmer K, Harper AA. Reactive oxygen species alters the electrophysiological properties and raises [Ca2+]i in intracardiac ganglion neurons. Am J Physiol Regul Integr Comp Physiol 2010; 299:R42-54. [PMID: 20445155 PMCID: PMC2917765 DOI: 10.1152/ajpregu.00053.2010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have investigated the effects of the reactive oxygen species (ROS) donors hydrogen peroxide (H2O2) and tert-butyl hydroperoxide (t-BHP) on the intrinsic electrophysiological characteristics: ganglionic transmission and resting [Ca2+]i in neonate and adult rat intracardiac ganglion (ICG) neurons. Intracellular recordings were made using sharp microelectrodes filled with either 0.5 M KCl or Oregon Green 488 BAPTA-1, allowing recording of electrical properties and measurement of [Ca2+]i. H2O2 and t-BHP both hyperpolarized the resting membrane potential and reduced membrane resistance. In adult ICG neurons, the hyperpolarizing action of H2O2 was reversed fully by Ba2+ and partially by tetraethylammonium, muscarine, and linopirdine. H2O2 and t-BHP reduced the action potential afterhyperpolarization (AHP) amplitude but had no impact on either overshoot or AHP duration. ROS donors evoked an increase in discharge adaptation to long depolarizing current pulses. H2O2 blocked ganglionic transmission in most ICG neurons but did not alter nicotine-evoked depolarizations. By contrast, t-BHP had no significant action on ganglionic transmission. H2O2 and t-BHP increased resting intracellular Ca2+ levels to 1.6 ( ± 0.6, n = 11, P < 0.01) and 1.6 ( ± 0.3, n = 8, P < 0.001), respectively, of control value (1.0, ∼60 nM). The ROS scavenger catalase prevented the actions of H2O2, and this protection extended beyond the period of application. Superoxide dismutase partially shielded against the action of H2O2, but this was limited to the period of application. These data demonstrate that ROS decreases the excitability and ganglionic transmission of ICG neurons, attenuating parasympathetic control of the heart.
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Affiliation(s)
- Jhansi Dyavanapalli
- Division of Molecular Physiology, James Black Centre, College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
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Mellor KM, Ritchie RH, Delbridge LMD. Reactive oxygen species and insulin-resistant cardiomyopathy. Clin Exp Pharmacol Physiol 2010; 37:222-8. [DOI: 10.1111/j.1440-1681.2009.05274.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Ramful D, Bahorun T, Bourdon E, Tarnus E, Aruoma OI. Bioactive phenolics and antioxidant propensity of flavedo extracts of Mauritian citrus fruits: potential prophylactic ingredients for functional foods application. Toxicology 2010; 278:75-87. [PMID: 20100535 DOI: 10.1016/j.tox.2010.01.012] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Revised: 01/11/2010] [Accepted: 01/18/2010] [Indexed: 11/25/2022]
Abstract
The flavedo extracts of twenty-one varieties of citrus fruits (oranges, satsumah, clementine, mandarins, tangor, bergamot, lemon, tangelos, kumquat, calamondin and pamplemousses) grown in Mauritius were examined for their total phenolic, flavonoid and vitamin C contents and antioxidant activities. Total phenolics correlated strongly with the trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant capacity (FRAP) and hypochlorous acid (HOCl) scavenging activity assays (r > 0.85). Based on their antioxidant activities in these three assays nine citrus fruits namely, one orange, clementine, tangor and pamplemousse variety, two tangelo varieties and three mandarin varieties, were further characterized for their flavanone, flavonol and flavone levels by HPLC and their antioxidant activities were assessed by the copper-phenanthroline and iron chelation assays. The flavanone, hesperidin, was present at the highest concentrations in all flavedo extracts except for pamplemousses where it was not detected. Contents in hesperidin ranged from 83 ± 0.06 to 234 ± 1.73 mg/g FW. Poncirin, didymin, diosmin, isorhoifolin and narirutin were also present in all extracts whereas naringin was present only in one mandarin variety. The nine flavedo extracts exhibited good DNA protecting ability in the cuphen assay with IC₅₀ values ranging from 6.3 ± 0.46 to 23.0 ± 0.48 mg FW/mL. Essentially the flavedos were able to chelate metal ions however, tangor was most effective with an IC₅₀ value of 9.1 ± 0.08 mg FW/mL. The flavedo extracts of citrus fruits represent a significant source of phenolic antioxidants with potential prophylactic properties for the development of functional foods.
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Affiliation(s)
- Deena Ramful
- Department of Agricultural and Food Science, Faculty of Agriculture, University of Mauritius, Réduit, Mauritius
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Gunter TE, Sheu SS. Characteristics and possible functions of mitochondrial Ca(2+) transport mechanisms. BIOCHIMICA ET BIOPHYSICA ACTA 2009; 1787:1291-308. [PMID: 19161975 PMCID: PMC2730425 DOI: 10.1016/j.bbabio.2008.12.011] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Revised: 12/22/2008] [Accepted: 12/29/2008] [Indexed: 02/07/2023]
Abstract
Mitochondria produce around 92% of the ATP used in the typical animal cell by oxidative phosphorylation using energy from their electrochemical proton gradient. Intramitochondrial free Ca(2+) concentration ([Ca(2+)](m)) has been found to be an important component of control of the rate of this ATP production. In addition, [Ca(2+)](m) also controls the opening of a large pore in the inner mitochondrial membrane, the permeability transition pore (PTP), which plays a role in mitochondrial control of programmed cell death or apoptosis. Therefore, [Ca(2+)](m) can control whether the cell has sufficient ATP to fulfill its functions and survive or is condemned to death. Ca(2+) is also one of the most important second messengers within the cytosol, signaling changes in cellular response through Ca(2+) pulses or transients. Mitochondria can also sequester Ca(2+) from these transients so as to modify the shape of Ca(2+) signaling transients or control their location within the cell. All of this is controlled by the action of four or five mitochondrial Ca(2+) transport mechanisms and the PTP. The characteristics of these mechanisms of Ca(2+) transport and a discussion of how they might function are described in this paper.
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Affiliation(s)
- Thomas E Gunter
- Department of Biochemistry and Biophysics and Mitochondrial Research and Innovation Group, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA.
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Halestrap AP, Pasdois P. The role of the mitochondrial permeability transition pore in heart disease. BIOCHIMICA ET BIOPHYSICA ACTA 2009; 1787:1402-15. [PMID: 19168026 DOI: 10.1016/j.bbabio.2008.12.017] [Citation(s) in RCA: 277] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Revised: 12/19/2008] [Accepted: 12/20/2008] [Indexed: 01/17/2023]
Abstract
Like Dr. Jeckyll and Mr. Hyde, mitochondria possess two distinct persona. Under normal physiological conditions they synthesise ATP to meet the energy needs of the beating heart. Here calcium acts as a signal to balance the rate of ATP production with ATP demand. However, when the heart is overloaded with calcium, especially when this is accompanied by oxidative stress, mitochondria embrace their darker side, and induce necrotic cell death of the myocytes. This happens acutely in reperfusion injury and chronically in congestive heart failure. Here calcium overload, adenine nucleotide depletion and oxidative stress combine forces to induce the opening of a non-specific pore in the mitochondrial membrane, known as the mitochondrial permeability transition pore (mPTP). The molecular nature of the mPTP remains controversial but current evidence implicates a matrix protein, cyclophilin-D (CyP-D) and two inner membrane proteins, the adenine nucleotide translocase (ANT) and the phosphate carrier (PiC). Inhibition of mPTP opening can be achieved with inhibitors of each component, but targeting CyP-D with cyclosporin A (CsA) and its non-immunosuppressive analogues is the best described. In animal models, inhibition of mPTP opening by either CsA or genetic ablation of CyP-D provides strong protection from both reperfusion injury and congestive heart failure. This confirms the mPTP as a promising drug target in human cardiovascular disease. Indeed, the first clinical trials have shown CsA treatment improves recovery after treatment of a coronary thrombosis with angioplasty.
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Affiliation(s)
- Andrew P Halestrap
- Department of Biochemistry and Bristol Heart Institute, University of Bristol, School of Medical Sciences, University Walk, Bristol BS8 1TD, UK.
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Abstract
1. Calcium is necessary for myocardial function, including contraction and maintenance of cardiac output. Calcium is also necessary for myocardial energetics and production of ATP by mitochondria, but the mechanisms for calcium regulation by mitochondria are still not fully resolved. 2. The cytoskeleton plays an important role in maintaining a cell's integrity. It is now recognized that cytoskeletal proteins can also assist in the transmission of signals from the plasma membrane to intracellular organelles. Cytoskeletal proteins can regulate the function of the L-type Ca(2+) channel and alter intracellular calcium homeostasis. 3. Recent evidence suggests that calcium influx through the L-type Ca(2+) channel is sufficient to alter a number of mitochondrial functional parameters, including superoxide production, NADH production and metabolic activity, assessed as the formation of formazan from tetrazolium salt. This occurs in a calcium-dependent manner. 4. Activation of the L-type Ca(2+) channel also alters mitochondrial membrane potential in a calcium-independent manner and this is assisted by movement of the auxiliary beta(2)-subunit through F-actin filaments. 5. Because the L-type Ca(2+) channel is the initiator of contraction, a functional coupling between the channels and mitochondria may assist in meeting myocardial energy demand on a beat-to-beat basis.
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Affiliation(s)
- Helena M Viola
- Cardiovascular Electrophysiology Laboratory, School of Biomedical Biomolecular and Chemical Sciences, The University of Western Australia, Crawley, Australia
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Xu H, Bai J, Meng J, Hao W, Xu H, Cao JM. Multi-walled carbon nanotubes suppress potassium channel activities in PC12 cells. NANOTECHNOLOGY 2009; 20:285102. [PMID: 19546493 DOI: 10.1088/0957-4484/20/28/285102] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The advancement in nanotechnology has produced technological and conceptual breakthroughs but the effects nanomaterials have on organisms at the cellular level are poorly understood. Here we report that carboxyl-terminated multi-walled carbon nanotubes (MWCNTs) act as antagonists of three types of potassium channels as assessed by whole-cell patch clamp electrophysiology on undifferentiated pheochromocytoma (PC12) cells. Our results showed that carboxyl-terminated MWCNTs suppress the current densities of I(to), I(K) and I(K1) in a time-dependent and irreversible manner. The suppressions were most distinct 24 h after incubation with MWCNTs. However, MWCNTs did not significantly change the expression levels of reactive oxygen species (ROS) or intracellular free calcium and also did not alter the mitochondrial membrane potential (DeltaPsi(m)) in PC12 cells. These results suggest that oxidative stress was not involved in the MWCNTs suppression of I(to), I(K) and I(K1) current densities. Nonetheless, the suppression of potassium currents by MWCNTs will impact on electrical signaling of excitable cells such as neurons and muscles.
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Affiliation(s)
- Haifei Xu
- Department of Physiology and Pathophysiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing, PR China
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Stowe DF, Camara AKS. Mitochondrial reactive oxygen species production in excitable cells: modulators of mitochondrial and cell function. Antioxid Redox Signal 2009; 11:1373-414. [PMID: 19187004 PMCID: PMC2842133 DOI: 10.1089/ars.2008.2331] [Citation(s) in RCA: 341] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 01/12/2009] [Accepted: 01/13/2009] [Indexed: 12/14/2022]
Abstract
The mitochondrion is a major source of reactive oxygen species (ROS). Superoxide (O(2)(*-)) is generated under specific bioenergetic conditions at several sites within the electron-transport system; most is converted to H(2)O(2) inside and outside the mitochondrial matrix by superoxide dismutases. H(2)O(2) is a major chemical messenger that, in low amounts and with its products, physiologically modulates cell function. The redox state and ROS scavengers largely control the emission (generation scavenging) of O(2)(*-). Cell ischemia, hypoxia, or toxins can result in excess O(2)(*-) production when the redox state is altered and the ROS scavenger systems are overwhelmed. Too much H(2)O(2) can combine with Fe(2+) complexes to form reactive ferryl species (e.g., Fe(IV) = O(*)). In the presence of nitric oxide (NO(*)), O(2)(*-) forms the reactant peroxynitrite (ONOO(-)), and ONOOH-induced nitrosylation of proteins, DNA, and lipids can modify their structure and function. An initial increase in ROS can cause an even greater increase in ROS and allow excess mitochondrial Ca(2+) entry, both of which are factors that induce cell apoptosis and necrosis. Approaches to reduce excess O(2)(*-) emission include selectively boosting the antioxidant capacity, uncoupling of oxidative phosphorylation to reduce generation of O(2)(*-) by inducing proton leak, and reversibly inhibiting electron transport. Mitochondrial cation channels and exchangers function to maintain matrix homeostasis and likely play a role in modulating mitochondrial function, in part by regulating O(2)(*-) generation. Cell-signaling pathways induced physiologically by ROS include effects on thiol groups and disulfide linkages to modify posttranslationally protein structure to activate/inactivate specific kinase/phosphatase pathways. Hypoxia-inducible factors that stimulate a cascade of gene transcription may be mediated physiologically by ROS. Our knowledge of the role played by ROS and their scavenging systems in modulation of cell function and cell death has grown exponentially over the past few years, but we are still limited in how to apply this knowledge to develop its full therapeutic potential.
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Affiliation(s)
- David F Stowe
- Anesthesiology Research Laboratories, Department of Anesthesiology, The Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
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Nazzaro P, Schirosi G, Clemente R, Battista L, Serio G, Boniello E, Carratù PL, Lacedonia D, Federico F, Resta O. Severe obstructive sleep apnoea exacerbates the microvascular impairment in very mild hypertensives. Eur J Clin Invest 2008; 38:766-73. [PMID: 18837802 DOI: 10.1111/j.1365-2362.2008.02011.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Different studies have shown that obstructive sleep apnoea syndrome (OSAS), frequently associated with hypertension, represents a harmful and independent risk for cardiovascular diseases. The aim of our study was to ascertain whether the occurrence of OSAS could worsen microcirculatory impairment in very mild hypertensives. MATERIALS AND METHODS One hundred untreated very mild hypertensives underwent polysomnography and subdivided into 32 non-OSAS, 33 mild OSAS and 35 severe OSAS patients on standardized criteria. They underwent routine blood chemistry, ambulatory blood pressure monitoring and anthropometric analysis. Skin capillary density (n mm(-2)) of forearm (FAC) and periungueal (PUC) fields was obtained through videocapillaroscopy. By a venous congestion manoeuvre, PUC was maximized (CVC) and secondary capillary recruitment (GAIN) was calculated. These measurements served as indices of structural and functional capillary rarefaction, respectively. RESULTS Severe OSAS hypertensives showed reduced FAC (P < 0.001) and PUC (P < 0.001) as compared to those with mild OSAS and non-OSAS, but a greater CVC (P < 0.01) and GAIN (P < 0.001). Multiple regression analysis showed that PUC was inversely related to total sleep time with oxyhaemoglobin saturation at < 90% (TST90) (P < 0.001) and FAC to the apnoea-hypopnoea index (AHI) (P < 0.001) and to the sleep propensity (P < 0.01). CVC was positively associated to AHI (P < 0.001) and GAIN to TST90 (P < 0.05). CONCLUSIONS The findings suggest that OSAS, by means of reduced basal and functional capillarity rarefaction, might pose an additional risk of impaired peripheral perfusion in very mild hypertensives. A microcirculation study therefore should be a part of the clinical approach in patients at high cerebro-cardiovascular risk such as hypertensives and patients with OSAS.
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Affiliation(s)
- P Nazzaro
- Department of Neurological and Psychiatric Sciences, Neurophysiopathology, Hypertension, Medical School of Bari, University of Bari, Bari, Italy.
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Bell D, Zhao Y, McCoy FPG, Devine AB, McDermott BJ. Differential Effects of an Anti-Oxidant Intervention on Cardiomyocyte Expression of Adrenomedullin and Intermedin and their Receptor Components in Chronic Nitric Oxide Deficiency. Cell Physiol Biochem 2008; 20:269-82. [PMID: 17762156 DOI: 10.1159/000107513] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/02/2007] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Chronic inhibition of nitric oxide (NO) synthesis is associated with hypertension, myocardial oxidative stress and hypertrophic remodeling. Up-regulation of the cardiomyocyte adrenomedullin (AM) / intermedin (IMD) receptor signaling cascade is also apparent in NO-deficient cardiomyocytes: augmented expression of AM and receptor activity modifying proteins RAMP2 and RAMP3 is prevented by blood pressure normalization while that of RAMP1 and intermedin (IMD) is not, indicating that the latter is regulated by a pressure-independent mechanism. AIMS to verify the ability of an anti-oxidant intervention to normalize cardiomyocyte oxidant status and to investigate the influence of such an intervention on expression of AM, IMD and their receptor components in NO-deficient cardiomyocytes. METHODS NO synthesis inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME, 35 mg/kg/day) was given to rats for 8 weeks, with/without con-current administration of antioxidants (Vitamin C (25mg/kg/day) and Tempol (25mg/kg/day)). RESULTS In left ventricular cardiomyocytes isolated from L-NAME treated rats, increased oxidative stress was indicated by augmented (3.6 fold) membrane protein oxidation, enhanced expression of catalytic and regulatory subunits of pro-oxidant NADPH oxidases (NOX1, NOX2) and compensatory increases in expression of anti-oxidant glutathione peroxidase and Cu/Zn superoxide dismutases (SOD1, SOD3). Vitamin C plus Tempol did not reduce systolic blood pressure but normalized augmented plasma levels of IMD, but not of AM, and in cardiomyocytes: (i) abolished increased membrane protein oxidation; (ii) normalized augmented expression of prepro-IMD and RAMP1, but not prepro-AM, RAMP2 and RAMP3; (iii) attenuated (by 42%) increased width and normalized expression of hypertrophic markers, skeletal-alpha-actin and prepro-endothelin-1 similarly to blood pressure normalization but in contrast to blood pressure normalization did not attenuate augmented brain natriuretic peptide (BNP) expression. CONCLUSION normalization specifically of augmented IMD/RAMP1 expression in NO-deficient cardiomyocytes by antioxidant intervention in the absence of blood pressure reduction indicates that these genes are likely to be induced directly by myocardial oxidative stress. Although oxidative stress contributed to cardiomyocyte hypertrophy, induction of IMD and RAMP1 is unlikely to be secondary to cardiomyocyte hypertrophy.
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Affiliation(s)
- David Bell
- Cardiovascular Research Group, School of Medicine and Dentistry, Queen's University Belfast, Whitla Medical Building, Northern Ireland.
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Kahlert S, Blaser T, Tulapurkar M, Reiser G. P2Y receptor-activating nucleotides modulate cellular reactive oxygen species production in dissociated hippocampal astrocytes and neurons in culture independent of parallel cytosolic Ca(2+) rise and change in mitochondrial potential. J Neurosci Res 2008; 85:3443-56. [PMID: 17492786 DOI: 10.1002/jnr.21316] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
With mixed cultures of hippocampal astrocytes and neurons, we investigated the influence of nucleotides on cytosolic Ca(2+) level, generation of reactive oxygen species (ROS), and mitochondrial potential. We employed ATP and four purine/pyrimidine derivates, which are P2Y receptor subtype-preferring agonists. Stimulation with ATP, a P2Y(1/2/4) receptor agonist in rat, caused a large cytosolic Ca(2+) increase in astrocytes and a considerably smaller Ca(2+) response in neighboring neurons. The P2Y(1) receptor antagonist MRS2179 completely blocked the ATP-induced Ca(2+) response in astrocytes and neurons. Application of ATP significantly reduced the mitochondrial potential in neurons, which was not inhibited by MRS2179. Interestingly, MRS2179 mediated a mitochondrial depolarization without affecting the cytosolic Ca(2+) level. Stimulation with UDP, a P2Y(6) receptor agonist; UTP, a P2Y(2/4) receptor agonist; 2MeSATP, a P2Y(1) receptor agonist; or 2MeSADP, a P2Y(1/12/13) receptor agonist, evoked significant Ca(2+) responses in astrocytes but small Ca(2+) responses in neurons. In astrocytes, there was an inverse relationship between the amplitude of the cytosolic Ca(2+) peak and the rate of ROS generation in response to nucleotide application. Activation with UDP resulted in the highest ROS generation that we detected, whereas 2MeSADP and 2MeSATP reduced the ROS generation below the basal level. 2MeSADP and UDP caused mitochondrial depolarization of comparable size. Thus, neither in astrocytes nor in neurons did the degree of mitochondrial depolarization correlate with ROS generation. Nucleotides acting via P2Y receptors can modulate ROS generation of hippocampal neurons without acutely changing the cytosolic Ca(2+) level. Thus, ROS might function as a signaling molecule upon nucleotide-induced P2Y receptor activation in brain.
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Affiliation(s)
- Stefan Kahlert
- Institut für Neurobiochemie, Medizinische Fakultät der Otto-von-Guericke-Universität Magdeburg, Magdeburg, Germany
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Lou YW, Chen YY, Hsu SF, Chen RK, Lee CL, Khoo KH, Tonks NK, Meng TC. Redox regulation of the protein tyrosine phosphatase PTP1B in cancer cells. FEBS J 2007; 275:69-88. [PMID: 18067579 DOI: 10.1111/j.1742-4658.2007.06173.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The oxidation and inactivation of protein tyrosine phosphatases is one mechanism by which reactive oxygen species influence tyrosine phosphorylation-dependent signaling events and exert their biological functions. In the present study, we determined the redox status of endogenous protein tyrosine phosphatases in HepG2 and A431 human cancer cells, in which reactive oxygen species are produced constitutively. We used mass spectrometry to assess the state of oxidation of the catalytic cysteine residue of endogenous PTP1B and show that this residue underwent both reversible and irreversible oxidation to high stoichiometry in response to intrinsic reactive oxygen species production. In addition, our data show that the oxidation of PTP1B is specific to the active site Cys, with the other Cys residues in the protein remaining in a reduced state. Treatment of these cells with diphenyleniodonium, an inhibitor of NADPH oxidases, decreased reactive oxygen species levels. This resulted in inhibition of protein tyrosine phosphatase oxidation, concomitant with decreased tyrosine phosphorylation of cellular proteins and inhibition of anchorage-independent cell growth. Therefore, our data also suggest that the high level of intrinsic reactive oxygen species may contribute to the transformed phenotype of HepG2 and A431 cells via constitutive inactivation of cellular protein tyrosine phosphatases.
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Affiliation(s)
- Yi-Wei Lou
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
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Karar J, Dolt KS, Mishra MK, Arif E, Javed S, Pasha MAQ. Expression and functional activity of pro-oxidants and antioxidants in murine heart exposed to acute hypobaric hypoxia. FEBS Lett 2007; 581:4577-82. [PMID: 17825300 DOI: 10.1016/j.febslet.2007.08.044] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 08/08/2007] [Accepted: 08/20/2007] [Indexed: 11/28/2022]
Abstract
Under hypobaric hypoxia, antioxidant defenses of the heart are stressed by the enhanced production of ROS. Mammalian heart acclimatizes to hypoxia through altered gene expression, which we studied in murine heart exposed to 10h of acute hypobaric hypoxia (AHH), equivalent to 15000ft, using cDNA arrays. Functional classification of genes with a > or =2-fold change revealed a number of pro-oxidants like Cyba, Xdh, Txnip, Ppp1r15b and antioxidants like Cat, Gpx1, Mt1, Mgst1. Interestingly, the protein level of Cyba, a subunit of NADPH oxidase, was markedly decreased in AHH exposed heart, suggesting the involvement of some stress response pathways. The AHH exposure also caused a significant reduction (50%) in the level of GSH (P<0.05). The present study provides a retrospective insight on the cellular antioxidant defense mechanisms under AHH.
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Affiliation(s)
- Jayashree Karar
- Institute of Genomics and Integrative Biology, Mall Road, Delhi 110 007, India
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Milner PI, Wilkins RJ, Gibson JS. The role of mitochondrial reactive oxygen species in pH regulation in articular chondrocytes. Osteoarthritis Cartilage 2007; 15:735-42. [PMID: 17306992 DOI: 10.1016/j.joca.2007.01.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Accepted: 01/06/2007] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To examine the effect of O(2) and the role, and source, of reactive oxygen species (ROS) on pH regulation in articular chondrocytes. METHODS Cartilage from equine metacarpo/tarsophalangeal joints was digested (collagenase) to isolate chondrocytes and loaded with 2',7'-bis-2-(carboxyethyl)-5(6)-carboxylfluorescein, a pH-sensitive fluorophore. O(2) tension was maintained using Eschweiler tonometers and a Wosthoff gas mixer. Cells were exposed to agents which alter ROS levels, mitochondrial inhibitors and/or inhibitors of protein phosphorylation. ROS levels were determined by dichlorofluorescein and mitochondrial membrane potential measured using JC-1. RESULTS pH homeostasis was dependent on ROS. Na(+)/H(+) exchanger (NHE) activity was inhibited at low O(2) tension (acid efflux reducing from 2.30+/-0.05 to 1.27+/-0.11mMmin(-1) at 1%). NHE activity correlated with ROS levels (r(2)=0.65). ROS levels were increased by antimycin A (with levels at 1% O(2) tension increasing from 59+/-9% of the value at 20% to 87+/-7%), but reduced by rotenone, myxothiazol and diphenyleneiodonium. Hypoxia induced depolarisation of the mitochondrial membrane potential (with JC-1 red-green fluorescence ratio at 1% O(2) tension decreasing to 40+/-10% of the value at 20%). The response to changes in O(2) and to antimycin A was inhibited by staurosporine, wortmanin and calyculin A. CONCLUSION The fall in ROS levels in hypoxia reduces the ability of articular chondrocytes to regulate pH, inhibiting NHE activity via changes in protein phosphorylation. The site of ROS generation is likely to be mitochondrial electron transport chain complex III. These effects are important to understanding normal chondrocyte function and response to altered O(2) tension.
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Affiliation(s)
- P I Milner
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
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Dada LA, Novoa E, Lecuona E, Sun H, Sznajder JI. Role of the small GTPase RhoA in the hypoxia-induced decrease of plasma membrane Na,K-ATPase in A549 cells. J Cell Sci 2007; 120:2214-22. [PMID: 17550967 DOI: 10.1242/jcs.003038] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Hypoxia impairs alveolar fluid reabsorption by promoting Na,K-ATPase endocytosis, from the plasma membrane of alveolar epithelial cells. The present study was designed to determine whether hypoxia induces Na,K-ATPase endocytosis via reactive oxygen species (ROS)-mediated RhoA activation. In A549 cells, RhoA activation occurred within 15 minutes of cells exposure to hypoxia. This activation was inhibited in cells infected with adenovirus coding for gluthatione peroxidase (an H2O2 scavenger), in mitochondria depleted (rho0) cells or cells expressing decreased levels of the Rieske iron-sulfur protein (inhibitor of mitochondrial complex III), which suggests a role for mitochondrial ROS. Moreover, exogenous H2O2 treatment during normoxia mimicked the effects of hypoxia on RhoA, further supporting a role for ROS. Cells expressing dominant negative RhoA failed to endocytose the Na,K-ATPase during hypoxia or after H2O2 treatment. Na,K-ATPase endocytosis was also prevented in cells treated with Y-27632, a Rho-associated kinase (ROCK) inhibitor, and in cells expressing dominant negative ROCK. In summary, we provide evidence that in human alveolar epithelial cells exposed to hypoxia, RhoA/ROCK activation is necessary for Na,K-ATPase endocytosis via a mechanism that requires mitochondrial ROS.
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Affiliation(s)
- Laura A Dada
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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Halestrap AP, Clarke SJ, Khaliulin I. The role of mitochondria in protection of the heart by preconditioning. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:1007-31. [PMID: 17631856 PMCID: PMC2212780 DOI: 10.1016/j.bbabio.2007.05.008] [Citation(s) in RCA: 299] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Revised: 05/18/2007] [Accepted: 05/23/2007] [Indexed: 12/16/2022]
Abstract
A prolonged period of ischaemia followed by reperfusion irreversibly damages the heart. Such reperfusion injury (RI) involves opening of the mitochondrial permeability transition pore (MPTP) under the conditions of calcium overload and oxidative stress that accompany reperfusion. Protection from MPTP opening and hence RI can be mediated by ischaemic preconditioning (IP) where the prolonged ischaemic period is preceded by one or more brief (2–5 min) cycles of ischaemia and reperfusion. Following a brief overview of the molecular characterisation and regulation of the MPTP, the proposed mechanisms by which IP reduces pore opening are reviewed including the potential roles for reactive oxygen species (ROS), protein kinase cascades, and mitochondrial potassium channels. It is proposed that IP-mediated inhibition of MPTP opening at reperfusion does not involve direct phosphorylation of mitochondrial proteins, but rather reflects diminished oxidative stress during prolonged ischaemia and reperfusion. This causes less oxidation of critical thiol groups on the MPTP that are known to sensitise pore opening to calcium. The mechanisms by which ROS levels are decreased in the IP hearts during prolonged ischaemia and reperfusion are not known, but appear to require activation of protein kinase Cε, either by receptor-mediated events or through transient increases in ROS during the IP protocol. Other signalling pathways may show cross-talk with this primary mechanism, but we suggest that a role for mitochondrial potassium channels is unlikely. The evidence for their activity in isolated mitochondria and cardiac myocytes is reviewed and the lack of specificity of the pharmacological agents used to implicate them in IP is noted. Some K+ channel openers uncouple mitochondria and others inhibit respiratory chain complexes, and their ability to produce ROS and precondition hearts is mimicked by bona fide uncouplers and respiratory chain inhibitors. IP may also provide continuing protection during reperfusion by preventing a cascade of MPTP-induced ROS production followed by further MPTP opening. This phase of protection may involve survival kinase pathways such as Akt and glycogen synthase kinase 3 (GSK3) either increasing ROS removal or reducing mitochondrial ROS production.
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Affiliation(s)
- Andrew P Halestrap
- Department of Biochemistry and Bristol Heart Institute, University of Bristol, School of Medical Sciences, University Walk, Bristol BS8 1TD, UK.
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Fernández-Velasco M, Ruiz-Hurtado G, Hurtado O, Moro MA, Delgado C. TNF-alpha downregulates transient outward potassium current in rat ventricular myocytes through iNOS overexpression and oxidant species generation. Am J Physiol Heart Circ Physiol 2007; 293:H238-45. [PMID: 17337591 DOI: 10.1152/ajpheart.01122.2006] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Tumor necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine that has been implicated in the pathogenesis of heart failure. Prolongation of the action potential duration and downregulation of several K(+) currents might participate in the genesis of arrhythmias associated with chronic heart failure. Little information is available related to the mechanism by which TNF-alpha modulates cardiac K(+) channels. The present study analyzes the effect of TNF-alpha on the transient outward K(+) current (I(to)) in rat ventricular myocytes, using the whole cell patch-clamp technique. We found that TNF-alpha is able to induce a significant reduction of I(to) density, modifies its inactivation, and downregulates the Kv4.2 protein expression, while calcium current density is not affected. We have also demonstrated that the reduction of I(to) density induced by TNF-alpha was prevented by the selective inducible nitric oxide synthase (iNOS) inhibitor 1400-W, the protein synthesis inhibitor cycloheximide, the antioxidant tocopherol, and the superoxide dismutase mimetic manganese(III) tetrakis (4-benzoic acid) porphyrin. In addition, a reduced I(to) density was recorded in ventricular myocytes exposed to peroxynitrite, supporting a possible participation of this oxidant in the effects of TNF-alpha on I(to). We conclude that TNF-alpha exposure, through iNOS induction and generation of oxidant species, promotes electrophysiological changes (decreased I(to) and action potential duration prolongation) in rat ventricular myocytes, providing new insights into how cytokines modulate K(+) channels in the heart.
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Affiliation(s)
- María Fernández-Velasco
- Institute of Pharmacology and Toxicology, CSIC-UCM School of Medicine, Universidad Complutense, 28040 Madrid, Spain
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Verkaart S, Koopman WJH, van Emst-de Vries SE, Nijtmans LGJ, van den Heuvel LWPJ, Smeitink JAM, Willems PHGM. Superoxide production is inversely related to complex I activity in inherited complex I deficiency. Biochim Biophys Acta Mol Basis Dis 2007; 1772:373-81. [PMID: 17289351 DOI: 10.1016/j.bbadis.2006.12.009] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2006] [Revised: 12/16/2006] [Accepted: 12/18/2006] [Indexed: 11/26/2022]
Abstract
Deficiency of NADH:ubiquinone oxidoreductase or complex I (CI) is the most common cause of disorders of the oxidative phosphorylation system in humans. Using life cell imaging and blue-native electrophoresis we quantitatively compared superoxide production and CI amount and activity in cultured skin fibroblasts of 7 healthy control subjects and 21 children with inherited isolated CI deficiency. Thirteen children had a disease causing mutation in one of the nuclear-encoded CI subunits, whereas in the remainder the genetic cause of the disease is not yet established. Superoxide production was significantly increased in all but two of the patient cell lines. An inverse relationship with the amount and residual activity of CI was observed. In agreement with this finding, rotenone, a potent inhibitor of CI activity, dose-dependently increased superoxide production in healthy control cells. Also in this case an inverse relationship with the residual activity of CI was observed. In sharp contrast, however, rotenone did not decrease the amount of CI. The data presented show that superoxide production is increased in inherited CI deficiency and that this increase is primarily a consequence of the reduction in cellular CI activity and not of a further leakage of electrons from mutationally malformed complexes.
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Affiliation(s)
- Sjoerd Verkaart
- Department of Membrane Biochemistry, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Milner PI, Fairfax TPA, Browning JA, Wilkins RJ, Gibson JS. The effect of O2 tension on pH homeostasis in equine articular chondrocytes. ACTA ACUST UNITED AC 2006; 54:3523-32. [PMID: 17075856 DOI: 10.1002/art.22209] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
OBJECTIVE To determine the effects of varying O(2) on pH homeostasis, based on the hypothesis that the function of articular chondrocytes is best understood at realistic O(2) tensions. METHODS Cartilage from equine metacarpophalangeal/tarsophalangeal joints was digested with collagenase to isolate chondrocytes, and then loaded with the pH-sensitive fluorophore 2',7'-bis-2-(carboxyethyl)-5(6)-carboxylfluorescein. The radioisotope(22)Na(+) was used to determine the kinetics of Na(+)/H(+) exchange (NHE) and the activity of the Na(+)/K(+) pump, and ATP levels were assessed with luciferin assays. Levels of reactive oxygen species (ROS) were determined using 2',7'-dichlorofluorescein diacetate. RESULTS The pH homeostasis was unaffected when comparing tissue maintained at 20% O(2) (the level in water-saturated air at 37 degrees C) with that at 5% O(2) (which approximates the normal level in healthy cartilage); however, an O(2) tension of <5% caused a fall in intracellular pH (pH(i)) and slowed pH(i) recovery following acidification, an effect mediated via inhibition of NHE activity (likely through acid extrusion by NHE isoform 1). The Na(+)/K(+) pump activity and intracellular ATP concentration were unaffected by hypoxia, but the levels of ROS were reduced. Hypoxic inhibition of NHE activity and the reduction in ROS levels were reversed by treatment with H(2)O(2), Co(2+), or antimycin A. Treatment with calyculin A also prevented hypoxic inhibition of NHE activity. CONCLUSION The ability of articular chondrocytes to carry out pH homeostasis is compromised when O(2) tensions fall below those normally experienced, via inhibition of NHE. The putative signal is a reduction in levels of ROS derived from mitochondria, acting via altered protein phosphorylation. This effect is relevant to both physiologic and pathologic states of lowered O(2), such as in chronic inflammation.
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Mironov SL, Langohr K. Modulation of synaptic and channel activities in the respiratory network of the mice by NO/cGMP signalling pathways. Brain Res 2006; 1130:73-82. [PMID: 17169346 DOI: 10.1016/j.brainres.2006.09.114] [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] [Received: 06/13/2006] [Revised: 09/05/2006] [Accepted: 09/17/2006] [Indexed: 11/17/2022]
Abstract
We examined signalling pathways which can involve NO as a second messenger in the respiratory network. In the functional slice preparation, NO donors depressed the respiratory motor output and enhanced its depression after brief episodes of hypoxia. In the inspiratory neurons, NO donors suppressed spontaneous excitatory and inhibitory synaptic currents, activated single K(ATP) channels and inhibited L-type Ca2+ channels. NO scavengers, PTIO and hemoglobin, and the blocker of NO synthase, N-monomethyl-L-arginine, induced effects opposite to those of NO donors and indicated the role of endogenously generated NO in the modulation of the respiratory activity. Using fluorescent dyes DAF-2 and DCF, we imaged NO and reactive oxygen species (ROS). Concentrations of NO and ROS increased during brief episodes of hypoxia and they both contributed to the activation of K(ATP) channels due to oxygen withdrawal. The oxidizing agent t-butyl-hydroperoxide acted similarly to NO donors but it did not interfere with the effects of NO. Increase in cGMP levels with 8-Br-cGMP reproduced the actions of NO donors and occluded the effects of their subsequent applications. We propose that in the respiratory neurons, a constitutive production of NO is responsible for a tonic activation of cGMP-coupled signalling pathways and changes in NO levels modulate the respiratory motor output by altering the activity of K(ATP) and L-type Ca2+ channels.
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Affiliation(s)
- Sergej L Mironov
- DFG-Center of Molecular Physiology of the Brain, Department of Neuro- and Sensory Physiology, Georg-August-University, Göttingen, Humboldtallee 23, 37073, Germany.
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