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Singh K, Teyani RL, Moniri NH. Agonists and hydrogen peroxide mediate hyperoxidation of β2-adrenergic receptor in airway epithelial cells: Implications for tachyphylaxis to β2-agonists in constrictive airway disorders. Biomed Pharmacother 2023; 168:115763. [PMID: 37865997 PMCID: PMC10842251 DOI: 10.1016/j.biopha.2023.115763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 10/06/2023] [Accepted: 10/17/2023] [Indexed: 10/24/2023] Open
Abstract
Asthma and other airway obstructive disorders are characterized by heightened inflammation and excessive airway epithelial cell reactive oxygen species (ROS), which give rise to a highly oxidative environment. After decades of use, β2-adrenergic receptor (β2AR) agonists remain at the forefront of treatment options for asthma, however, chronic use of β2-agonists leads to tachyphylaxis to the bronchorelaxant effects, a phenomenon that remains mechanistically unexplained. We have previously demonstrated that β2AR agonism increases ROS generation in airway epithelial cells, which upholds proper receptor function via feedback oxidation of β2AR cysteine thiolates to Cys-S-sulfenic acids (Cys-SOH). Our previous results also demonstrate that prevention of normal redox cycling of this post-translational oxi-modification back to the thiol prevents proper receptor function. Given that Cys-S-sulfenic acids can be irreversibly overoxidized to Cys-S-sulfinic (Cys-SO2H) or S-sulfonic (Cys-SO3H) acids, which are incapable of further participation in redox reactions, we hypothesized that β2-agonist tachyphylaxis may be explained by hyperoxidation of β2AR to S-sulfinic acids. Here, using airway epithelial cell lines and primary small airway epithelial cells from healthy and asthma-diseased donors, we show that β2AR agonism generates H2O2 in a receptor and NAPDH oxidase-dependent manner. We also demonstrate that acute and chronic receptor agonism can facilitate β2AR S-sulfination, and that millimolar H2O2 concentrations are deleterious to β2AR-mediated cAMP formation, an effect that can be rescued to a degree in the presence of the cysteine-donating antioxidant N-acetyl-L-cysteine. Our results reveal that the oxidative state of β2AR may contribute to receptor functionality and may, at least in part, explain β2-agonist tachyphylaxis.
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Affiliation(s)
- Kirti Singh
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, GA 30341, USA
| | - Razan L Teyani
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, GA 30341, USA
| | - Nader H Moniri
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, GA 30341, USA; Department of Biomedical Sciences, School of Medicine, Mercer University Health Sciences Center, Mercer University, Macon, GA 31207, USA.
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2
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Palombo P, Bürkle A, Moreno-Villanueva M. Culture medium-dependent isoproterenol stability and its impact on DNA strand breaks formation and repair. Chem Biol Interact 2022; 357:109877. [PMID: 35276129 DOI: 10.1016/j.cbi.2022.109877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 02/06/2022] [Accepted: 02/28/2022] [Indexed: 11/18/2022]
Abstract
In vitro mechanistic research is mostly performed without taking into consideration the potential influence of cell culture media and/or their supplements and therefore, interactions between compounds of interest and medium ingredients may be overlooked. Isoproterenol (isoprenaline) is a synthetic catecholamine used as sympathomimetic drug that stimulates β-adrenergic receptors and is widely used in biomedical research. Clinical studies have shown that isoproterenol is rapidly metabolized in the human body with a plasma half-life of about 2-5 min. However, despite its use in many in vitro and ex vivo studies, the stability of isoproterenol in cell culture media has not been characterized. Our results show a decrease of isoproterenol concentration in RPMI medium but high stability of the compound in TexMACS medium. The isoproterenol oxidation product isoprenochrome forms during treatment in both media. However, isoprenochrome formation is significantly lower in TexMACS medium. The effective level of isoproterenol and the formation of oxidation products might explain the discrepancies observed in isoproterenol-induced genotoxicity and cytotoxicity.
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Affiliation(s)
- Philipp Palombo
- Molecular Toxicology Group, Department of Biology, Box 628, University of Konstanz, 78457, Konstanz, Germany.
| | - Alexander Bürkle
- Molecular Toxicology Group, Department of Biology, Box 628, University of Konstanz, 78457, Konstanz, Germany.
| | - Maria Moreno-Villanueva
- Molecular Toxicology Group, Department of Biology, Box 628, University of Konstanz, 78457, Konstanz, Germany; Human Performance Research Centre, Department of Sport Science, Box 30, University of Konstanz, 78457, Konstanz, Germany.
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3
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Singh K, Senatorov IS, Cheshmehkani A, Karmokar PF, Moniri NH. The skeletal muscle relaxer cyclobenzaprine is a potent non-competitive antagonist of histamine H1 receptors. J Pharmacol Exp Ther 2022; 380:202-209. [PMID: 34992159 DOI: 10.1124/jpet.121.000998] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 01/02/2021] [Indexed: 11/22/2022] Open
Abstract
Cyclobenzaprine is a tricyclic dimethylpropanamine skeletal muscle relaxant, which is used clinically to decrease muscle spasm and hypercontractility, as well as acute musculoskeletal pain. Although the absolute mechanism of action of cyclobenzaprine remains elusive, it is known to mediate its effects centrally, via inhibition of tonic somatic motor function, likely through modulation of noradrenergic and serotonergic systems. While cyclobenzaprine is effective as a muscle relaxant, greater than 30% of patients experience drowsiness and sedative/hypnotic effects, yet, the mechanisms that cause this adverse effect is also undescribed. Based on this common adverse effect profile and the structural similarity of cyclobenzaprine to tricyclic antidepressants, as well as ethanolamine first-generation antihistamines, we hypothesized that cyclobenzaprine facilitates sedative effects via off-target antagonism of central histamine H1 receptors (H1R). Here, for the first time, we present data that demonstrate that cyclobenzaprine exhibits low nanomolar affinity for the cloned human H1R, as well as that expressed in both rat and mouse brain. Using saturation radioligand binding, we also demonstrate that cyclobenzaprine binds to the H1R in a non-competitive manner. Similarly, functional assays measuring both Ca+2 influx and novel TRUPATH G-protein subunit BRET biosensors reveal that cyclobenzaprine also blocks histamine-mediated H1R functional activity in a non-competitive manner, whereas the classical H1R antagonist diphenhydramine does so competitively. Given that cyclobenzaprine readily crosses the blood-brain barrier and its muscle relaxant effects occur centrally, our data suggest that off-target central antagonism of H1R by cyclobenzaprine facilitates the significant sedative effect of this agent seen in patients. Significance Statement Cyclobenzaprine, a clinically used muscle relaxant that is strongly linked to sedation, demonstrates high affinity non-competitive antagonism at the histamine H1 receptor. This effect likely modulates the high degree of sedation patients experience.
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Affiliation(s)
- Kirti Singh
- Pharmaceutical Sciences, Mercer University, United States
| | | | | | | | - Nader H Moniri
- Pharmaceutical Sciences, Mercer Univeristy, United States
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4
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Michaeloudes C, Abubakar-Waziri H, Lakhdar R, Raby K, Dixey P, Adcock IM, Mumby S, Bhavsar PK, Chung KF. Molecular mechanisms of oxidative stress in asthma. Mol Aspects Med 2021; 85:101026. [PMID: 34625291 DOI: 10.1016/j.mam.2021.101026] [Citation(s) in RCA: 91] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 09/15/2021] [Indexed: 01/18/2023]
Abstract
The lungs are exposed to reactive oxygen species oxygen (ROS) produced as a result of inhalation of oxygen, as well as smoke and other air pollutants. Cell metabolism and the NADPH oxidases (Nox) generate low levels of intracellular ROS that act as signal transduction mediators by inducing oxidative modifications of histones, enzymes and transcription factors. Redox signalling is also regulated by localised production and sensing of ROS in mitochondria, the endoplasmic reticulum (ER) and inside the nucleus. Intracellular ROS are maintained at low levels through the action of a battery of enzymatic and non-enzymatic antioxidants. Asthma is a heterogeneous airway inflammatory disease with different immune endotypes; these include atopic or non-atopic Th2 type immune response associated with eosinophilia, or a non-Th2 response associated with neutrophilia. Airway remodelling and hyperresponsiveness accompany the inflammatory response in asthma. Over-production of ROS resulting from infiltrating immune cells, particularly eosinophils and neutrophils, and a concomitant impairment of antioxidant responses lead to development of oxidative stress in asthma. Oxidative stress is augmented in severe asthma and during exacerbations, as well as by air pollution and obesity, and causes oxidative damage of tissues promoting airway inflammation and hyperresponsiveness. Furthermore, deregulated Nox activity, mitochondrial dysfunction, ER stress and/or oxidative DNA damage, resulting from exposure to irritants, inflammatory mediators or obesity, may lead to redox-dependent changes in cell signalling. ROS play a central role in airway epithelium-mediated sensing, development of innate and adaptive immune responses, and airway remodelling and hyperresponsiveness. Nonetheless, antioxidant compounds have proven clinically ineffective as therapeutic agents for asthma, partly due to issues with stability and in vivo metabolism of these compounds. The compartmentalised nature of ROS production and sensing, and the role of ROS in homeostatic responses and in the action of corticosteroids and β2-adrenergic receptor agonists, adds another layer of complexity to antioxidant therapy development. Nox inhibitors and mitochondrial-targeted antioxidants are in clinical development for a number of diseases but they have not yet been investigated in asthma. A better understanding of the complex role of ROS in the pathogenesis of asthma will highlight new opportunities for more targeted and effective redox therapies.
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Affiliation(s)
- Charalambos Michaeloudes
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; NIHR Imperial Biomedical Research Centre, United Kingdom.
| | - Hisham Abubakar-Waziri
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; NIHR Imperial Biomedical Research Centre, United Kingdom
| | - Ramzi Lakhdar
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Katie Raby
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Piers Dixey
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; NIHR Imperial Biomedical Research Centre, United Kingdom
| | - Ian M Adcock
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; NIHR Imperial Biomedical Research Centre, United Kingdom
| | - Sharon Mumby
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; NIHR Imperial Biomedical Research Centre, United Kingdom
| | - Pankaj K Bhavsar
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; NIHR Imperial Biomedical Research Centre, United Kingdom
| | - Kian Fan Chung
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; NIHR Imperial Biomedical Research Centre, United Kingdom; Royal Brompton & Harefield NHS Trust, London, UK
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Adrenergic and Glucocorticoid Receptors in the Pulmonary Health Effects of Air Pollution. TOXICS 2021; 9:toxics9060132. [PMID: 34200050 PMCID: PMC8226814 DOI: 10.3390/toxics9060132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/28/2021] [Accepted: 05/31/2021] [Indexed: 01/16/2023]
Abstract
Adrenergic receptors (ARs) and glucocorticoid receptors (GRs) are activated by circulating catecholamines and glucocorticoids, respectively. These receptors regulate the homeostasis of physiological processes with specificity via multiple receptor subtypes, wide tissue-specific distribution, and interactions with other receptors and signaling processes. Based on their physiological roles, ARs and GRs are widely manipulated therapeutically for chronic diseases. Although these receptors play key roles in inflammatory and cellular homeostatic processes, little research has addressed their involvement in the health effects of air pollution. We have recently demonstrated that ozone, a prototypic air pollutant, mediates pulmonary and systemic effects through the activation of these receptors. A single exposure to ozone induces the sympathetic–adrenal–medullary and hypothalamic–pituitary–adrenal axes, resulting in the release of epinephrine and corticosterone into the circulation. These hormones act as ligands for ARs and GRs. The roles of beta AR (βARs) and GRs in ozone-induced pulmonary injury and inflammation were confirmed in a number of studies using interventional approaches. Accordingly, the activation status of ARs and GRs is critical in mediating the health effects of inhaled irritants. In this paper, we review the cellular distribution and functions of ARs and GRs, their lung-specific localization, and their involvement in ozone-induced health effects, in order to capture attention for future research.
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Chitre NM, Wood BJ, Ray A, Moniri NH, Murnane KS. Docosahexaenoic acid protects motor function and increases dopamine synthesis in a rat model of Parkinson's disease via mechanisms associated with increased protein kinase activity in the striatum. Neuropharmacology 2020; 167:107976. [PMID: 32001239 PMCID: PMC7110909 DOI: 10.1016/j.neuropharm.2020.107976] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 01/22/2020] [Accepted: 01/23/2020] [Indexed: 02/06/2023]
Abstract
Parkinson's disease (PD) is a devastating neurodegenerative disease that leads to motor deficits and selective destruction of nigrostriatal dopaminergic neurons. PD is typically treated by dopamine replacement agents; however, dopamine replacement loses effectiveness in the later stages of the disease. Here, we describe the neuroprotective effects of the omega-3 fatty acid docosahexaenoic acid (DHA) in the medial forebrain bundle 6-hydroxydopamine (6-OHDA) model of advanced-stage PD in rats. We show that daily administration of DHA protects against core symptoms of PD, including deficits in postural stability, gait integrity, and dopamine neurochemistry in motor areas of the striatum. Our results also demonstrate that DHA increases striatal dopamine synthesis via phosphorylation of the rate-limiting catecholamine synthesizing enzyme tyrosine hydroxylase, in a manner dependent on the second messenger-linked protein kinases PKA and PKC. We also show that DHA specifically reverses dopamine loss in the nigrostriatal pathway, with no effect in the mesolimbic or mesocortical pathways. This suggests that DHA is unlikely to produce pharmacotherapeutic or adverse effects that depend on dopamine pathways other than the nigrostriatal pathway. To our knowledge, previous reports have not examined the effects of DHA in such an advanced-stage model, documented that the dopamine synthesizing effects of DHA in vivo are mediated through the activation of protein kinases and regulation of TH activity, or demonstrated specificity to the nigrostriatal pathway. These novel findings corroborate the beneficial effects of omega-3 fatty acids seen in PD patients and suggest that DHA provides a novel means of protecting patients for dopamine neurodegeneration.
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Affiliation(s)
- Neha Milind Chitre
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, GA, USA
| | - Bo Jarrett Wood
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, GA, USA
| | - Azizi Ray
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, GA, USA
| | - Nader H Moniri
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, GA, USA
| | - Kevin Sean Murnane
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, GA, USA.
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7
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Senatorov IS, Cheshmehkani A, Burns RN, Singh K, Moniri NH. Carboxy-Terminal Phosphoregulation of the Long Splice Isoform of Free-Fatty Acid Receptor-4 Mediates β-Arrestin Recruitment and Signaling to ERK1/2. Mol Pharmacol 2020; 97:304-313. [PMID: 32132133 DOI: 10.1124/mol.119.117697] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 01/31/2020] [Indexed: 12/13/2022] Open
Abstract
Free-fatty acid receptor-4 (FFA4), previously termed GPR120, is a G protein-coupled receptor (GPCR) for medium and long-chained fatty acids, agonism of which can regulate a myriad of metabolic, sensory, inflammatory, and proliferatory signals. Two alternative splice isoforms of FFA4 exist that differ by the presence of an additional 16 amino acids in the longer (FFA4-L) transcript, which has been suggested to be an intrinsically β-arrestin-biased GPCR. Although the shorter isoform (FFA4-S) has been studied more extensively, very little is known about mechanisms of regulation or signaling of the longer isoform. Because β-arrestin recruitment is dependent on receptor phosphorylation, in the current study, we used the endogenous agonist docosahexaenoic acid (DHA) to examine the mechanisms of FFA4-L phosphorylation, as well as DHA-dependent β-arrestin recruitment and DHA-dependent extracellular-signal regulated kinase-1/2 (ERK1/2) signaling in human embryonic kidney 293 cells. Our results reveal differences in basal phosphorylation of the two FFA4 isoforms, and we show that DHA-mediated phosphorylation of FFA4-L is primarily regulated by G protein-coupled receptor kinase 6, whereas protein kinase-C can also contribute to agonist-induced and heterologous phosphorylation. Moreover, our data demonstrate that FFA4-L phosphorylation occurs on the distal C terminus and is directly responsible for recruitment and interactions with β-arrestin-2. Finally, using CRISPR/Cas9 genome-edited cells, our data reveal that unlike FFA4-S, the longer isoform is unable to facilitate phosphorylation of ERK1/2 in cells that are devoid of β-arrestin-1/2. Together, these results are the first to demonstrate phosphoregulation of FFA4-L as well as the effects of loss of phosphorylation sites on β-arrestin recruitment and ERK1/2 activation. SIGNIFICANCE STATEMENT: Free-fatty acid receptor-4 (FFA4) is a cell-surface G protein-coupled receptor for medium and long-chained fatty acids that can be expressed as distinct short (FFA4-S) or long (FFA4-L) isoforms. Although much is known about FFA4-S, the longer isoform remains virtually unstudied. Here, we reveal the mechanisms of docosahexaenoic acid-induced phosphorylation of FFA4-L and subsequent β-arrestin-2 recruitment and extracellular-signal regulated kinase-1/2 activity.
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Affiliation(s)
- Ilya S Senatorov
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, Georgia
| | - Ameneh Cheshmehkani
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, Georgia
| | - Rebecca N Burns
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, Georgia
| | - Kirti Singh
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, Georgia
| | - Nader H Moniri
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, Georgia
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8
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Rambacher KM, Moniri NH. Cysteine redox state regulates human β2-adrenergic receptor binding and function. Sci Rep 2020; 10:2934. [PMID: 32076070 PMCID: PMC7031529 DOI: 10.1038/s41598-020-59983-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 02/05/2020] [Indexed: 01/08/2023] Open
Abstract
Bronchoconstrictive airway disorders such as asthma are characterized by inflammation and increases in reactive oxygen species (ROS), which produce a highly oxidative environment. β2-adrenergic receptor (β2AR) agonists are a mainstay of clinical therapy for asthma and provide bronchorelaxation upon inhalation. We have previously shown that β2AR agonism generates intracellular ROS, an effect that is required for receptor function, and which post-translationally oxidizes β2AR cysteine thiols to Cys-S-sulfenic acids (Cys-S-OH). Furthermore, highly oxidative environments can irreversibly oxidize Cys-S-OH to Cys-S-sulfinic (Cys-SO2H) or S-sulfonic (Cys-SO3H) acids, which are incapable of further participating in homeostatic redox reactions (i.e., redox-deficient). The aim of this study was to examine the vitality of β2AR-ROS interplay and the resultant functional consequences of β2AR Cys-redox in the receptors native, oxidized, and redox-deficient states. Here, we show for the first time that β2AR can be oxidized to Cys-S-OH in situ, moreover, using both clonal cells and a human airway epithelial cell line endogenously expressing β2AR, we show that receptor redox state profoundly influences β2AR orthosteric ligand binding and downstream function. Specifically, homeostatic β2AR redox states are vital toward agonist-induced cAMP formation and subsequent CREB and G-protein-dependent ERK1/2 phosphorylation, in addition to β-arrestin-2 recruitment and downstream arrestin-dependent ERK1/2 phosphorylation and internalization. On the contrary, redox-deficient β2AR states exhibit decreased ability to signal via either Gαs or β-arrestin. Together, our results demonstrate a β2AR-ROS redox axis, which if disturbed, interferes with proper receptor function.
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Affiliation(s)
- Kalyn M Rambacher
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, GA30341, United States
| | - Nader H Moniri
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, GA30341, United States.
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9
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Rambacher KM, Moniri NH. The β2-adrenergic receptor-ROS signaling axis: An overlooked component of β2AR function? Biochem Pharmacol 2019; 171:113690. [PMID: 31697929 DOI: 10.1016/j.bcp.2019.113690] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 10/31/2019] [Indexed: 02/07/2023]
Abstract
β2-Adrenergic receptor (β2AR) agonists are clinically used to elicit rapid bronchodilation for the treatment of bronchospasms in pulmonary diseases such as asthma and COPD, both of which exhibit characteristically high levels of reactive oxygen species (ROS); likely secondary to over-expression of ROS generating enzymes and chronically heightened inflammation. Interestingly, β2AR has long-been linked to ROS, yet the involvement of ROS in β2AR function has not been as vigorously studied as other aspects of β2AR signaling. Herein, we discuss the existing body of evidence linking β2AR activation to intracellular ROS generation and importantly, the role of ROS in regulating β2AR function. The reciprocal interplay of the β2AR and ROS appear to endow this receptor with the ability to self-regulate signaling efficacy and ligand binding, hereby unveiling a redox-axis that may be unfavorably altered in pathological states contributing to both disease progression and therapeutic drug responses.
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Affiliation(s)
- Kalyn M Rambacher
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, GA 30341, USA
| | - Nader H Moniri
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University Health Sciences Center, Mercer University, Atlanta, GA 30341, USA.
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10
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Impaired PARP activity in response to the β-adrenergic receptor agonist isoproterenol. Toxicol In Vitro 2018; 50:29-39. [PMID: 29438734 DOI: 10.1016/j.tiv.2018.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 02/01/2018] [Accepted: 02/02/2018] [Indexed: 01/23/2023]
Abstract
Psychological stress has been associated with DNA damage, thus increasing the risk of numerous diseases including cancer. Here, we investigate the effect of acute and chronic stress on poly(ADP-ribose) polymerase-1 (PARP-1), a sensor of DNA damage and DNA repair initiator. In order to mimic the chronic release of epinephrine, human peripheral blood mononuclear cells (PBMCs) were treated repeatedly with the sympathomimetic drug isoproterenol. We found significant induction of DNA strand breaks that remained unrepaired 24 h after ex vivo incubation. Isoproterenol-induced DNA strand breaks could be partially prevented by pre-treatment with the β-adrenergic receptor antagonist propranolol. Furthermore, the level of PARP-1 protein and PARP activity decreased and the levels of the PARP substrate nicotinamide adenine dinucleotide (NAD+) and of adenosine triphosphate (ATP), necessary to replenish NAD+ pools, were lowered by isoproterenol treatment. In conclusion our data provide novel insights into the mechanisms of isoproterenol-induced genotoxicity linking β-adrenergic stimulation and PARP-1.
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Reich M, Deutschmann K, Sommerfeld A, Klindt C, Kluge S, Kubitz R, Ullmer C, Knoefel WT, Herebian D, Mayatepek E, Häussinger D, Keitel V. TGR5 is essential for bile acid-dependent cholangiocyte proliferation in vivo and in vitro. Gut 2016; 65:487-501. [PMID: 26420419 DOI: 10.1136/gutjnl-2015-309458] [Citation(s) in RCA: 129] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 09/01/2015] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Cholestatic liver diseases in humans as well as bile acid (BA)-feeding and common bile duct ligation (CBDL) in rodents trigger hyperplasia of cholangiocytes within the portal fields. Furthermore, elevation of BA levels enhances proliferation and invasiveness of cholangiocarcinoma (CCA) cells in animal models, thus promoting tumour progression. TGR5 is a G-protein coupled BA receptor, which is highly expressed in cholangiocytes and postulated to mediate the proliferative effects of BA. DESIGN BA-dependent cholangiocyte proliferation was examined in TGR5-knockout and wild type mice following cholic acid (CA)-feeding and CBDL. TGR5-dependent proliferation and protection from apoptosis was studied in isolated cholangiocytes and CCA cell lines following stimulation with TGR5 ligands and kinase inhibitors. TGR5 expression was analysed in human CCA tissue. RESULTS Cholangiocyte proliferation was significantly reduced in TGR5-knockout mice in response to CA-feeding and CBDL. Taurolithocholic acid and TGR5-selective agonists induced cholangiocyte proliferation through elevation of reactive oxygen species and cSrc mediated epidermal growth factor receptor transactivation and subsequent Erk1/2 phosphorylation only in wild type but not in TGR5-knockout-derived cells. In human CCA tissue TGR5 was overexpressed and the pathway of TGR5-dependent proliferation via epidermal growth factor receptor and extracellular signal-regulated kinase (ERK)1/2 activation also translated to CCA cell lines. Furthermore, apoptosis was inhibited by TGR5-dependent CD95 receptor serine phosphorylation. CONCLUSIONS TGR5 is an important mediator of BA-induced cholangiocyte proliferation in vivo and in vitro. Furthermore, TGR5 protects cholangiocytes from death receptor-mediated apoptosis. These mechanisms may protect cholangiocytes from BA toxicity under cholestatic conditions, however, they may trigger proliferation and apoptosis resistance in malignantly transformed cholangiocytes, thus promoting CCA progression.
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Affiliation(s)
- Maria Reich
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
| | - Kathleen Deutschmann
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
| | - Annika Sommerfeld
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
| | - Caroline Klindt
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
| | - Stefanie Kluge
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
| | - Ralf Kubitz
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
| | - Christoph Ullmer
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, Basel, Switzerland
| | - Wolfram T Knoefel
- Department of General, Visceral, and Pediatric Surgery, Heinrich-Heine-University, Düsseldorf, Germany
| | - Diran Herebian
- Department of General Pediatrics, Neonatalogy and Pediatric Cardiology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Ertan Mayatepek
- Department of General Pediatrics, Neonatalogy and Pediatric Cardiology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Dieter Häussinger
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
| | - Verena Keitel
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
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Chen W, Liu DJ, Huo YM, Wu ZY, Sun YW. Reactive oxygen species are involved in regulating hypocontractility of mesenteric artery to norepinephrine in cirrhotic rats with portal hypertension. Int J Biol Sci 2014; 10:386-95. [PMID: 24719556 PMCID: PMC3979991 DOI: 10.7150/ijbs.8081] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 02/18/2014] [Indexed: 12/19/2022] Open
Abstract
Background: Oxidative stress is involved in the hypocontractility of visceral artery to vasoconstrictors and formation of hyperdynamic circulation in cirrhosis with portal hypertension. In the present study, we investigated the effect of reactive oxygen species (ROS) on the mesenteric artery contractility in CCl4-induced cirrhotic rats, and the roles of G protein-coupled receptors (GPCRs) desensitization and RhoA /Rho associated coiled-coil forming protein kinase (ROCK) pathways. Methods: The mesenteric artery contraction to norepinephrine (NE) was determined by vessel perfusion system following treatments with apocynin, tempol or PEG-catalase. The protein expression of α1 adrenergic receptor, β-arrestin-2, ROCK-1, moesin and p-moesin was measured by western blot. The interaction between α1 adrenergic receptor and β-arrestin-2 was assessed by co-immunoprecipitation. Results: Pretreatment with apocynin or PEG-catalase in cirrhotic rats, the hydrogen peroxide level in the mesenteric arteriole was significantly decreased, and the dose-response curve of mesenteric arteriole to NE moved to the left with EC50 decreased. There was no significant change for the expression of α1 adrenergic receptor. However, the protein expression of β-arrestin-2 and its affinity with α1 adrenergic receptor were significantly decreased. The ROCK-1 activity and anti- Y-27632 inhibition in cirrhotic rats increased significantly with the protein expression unchanged. Such effects were not observed in tempol-treated group. Conclusion: The H2O2 decrease in mesenteric artery from rats with cirrhosis resulted in down regulation of the β-arrestin-2 expression and its binding ability with α1 adrenergic receptor, thereby affecting the agonist-induced ROCK activation and improving the contractile response in blood vessels.
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Affiliation(s)
- Wei Chen
- Department of Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - De-Jun Liu
- Department of Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Yan-Miao Huo
- Department of Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Zhi-Yong Wu
- Department of Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Yong-Wei Sun
- Department of Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
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13
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Burns RN, Singh M, Senatorov IS, Moniri NH. Mechanisms of homologous and heterologous phosphorylation of FFA receptor 4 (GPR120): GRK6 and PKC mediate phosphorylation of Thr³⁴⁷, Ser³⁵⁰, and Ser³⁵⁷ in the C-terminal tail. Biochem Pharmacol 2014; 87:650-9. [PMID: 24412271 DOI: 10.1016/j.bcp.2013.12.016] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 12/26/2013] [Accepted: 12/27/2013] [Indexed: 01/26/2023]
Abstract
Free fatty acid receptor 4 (FFA4), previously known as GPR120, is a G protein-coupled receptor that promotes numerous anti-inflammatory and antidiabetic effects upon its agonism by long chained unsaturated fatty acids. We have previously demonstrated that agonism of FFA4 with docosahexaenoic acid (DHA) and alpha-linoleic acid (ALA) facilitates rapid and transient phosphorylation of FFA4 expressed ectopically on the surface of HEK293 cells. However, the precise mechanisms that promote FFA4 phosphorylation remain elusive. In the current study, we examined the mechanisms behind both heterologous and homologous phosphorylation of FFA4 and set out to identify the foci of FFA4 phosphorylation. Our results demonstrate that basal and heterologous phosphorylation of FFA4 are mediated by protein kinase C (PKC), while G protein-coupled receptor kinase 6 (GRK6) plays the predominant role in DHA-mediated phosphorylation of FFA4. Furthermore, we identify Thr(347), Ser(350), and Ser(357) in the C-terminal tail as major sites of FFA4 phosphorylation. Concurrent mutation of these three sites leads to a FFA4 receptor that seemingly affects Gαq/11 signaling in a positive manner as demonstrated by heightened intracellular Ca(2+) responses following agonism with DHA. Importantly, this phosphodefective FFA4 mutant lacked the ability to promote β-arrestin-2 recruitment to the cell membrane. Since many of the functionally beneficial physiological effects of FFA4 are noted to be β-arrestin mediated, these findings could provide insight into the structural requirements for FFA4 function.
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Affiliation(s)
- Rebecca N Burns
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, Atlanta, GA 30341, USA
| | - Monalisa Singh
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, Atlanta, GA 30341, USA
| | - Ilya S Senatorov
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, Atlanta, GA 30341, USA
| | - Nader H Moniri
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, Atlanta, GA 30341, USA.
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14
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Cagnone GLM, Sirard MA. Transcriptomic signature to oxidative stress exposure at the time of embryonic genome activation in bovine blastocysts. Mol Reprod Dev 2013; 80:297-314. [PMID: 23426876 DOI: 10.1002/mrd.22162] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 02/07/2013] [Indexed: 12/20/2022]
Abstract
In order to understand how in vitro culture affects embryonic quality, we analyzed survival and global gene expression in bovine blastocysts after exposure to increased oxidative stress conditions. Two pro-oxidant agents, one that acts extracellularly by promoting reactive oxygen species (ROS) production (0.01 mM 2,2'-azobis (2-amidinopropane) dihydrochloride [AAPH]) or another that acts intracellularly by inhibiting glutathione synthesis (0.4 mM buthionine sulfoximine [BSO]) were added separately to in vitro culture media from Day 3 (8-16-cell stage) onward. Transcriptomic analysis was then performed on resulting Day-7 blastocysts. In the literature, these two pro-oxidant conditions were shown to induce delayed degeneration in a proportion of Day-8 blastocysts. In our experiment, no morphological difference was visible, but AAPH tended to decrease the blastocyst rate while BSO significantly reduced it, indicating a differential impact on the surviving population. At the transcriptomic level, blastocysts that survived either pro-oxidant exposure showed oxidative stress and an inflammatory response (ARRB2), although AAPH induced higher disturbances in cellular homeostasis (SERPINE1). Functional genomics of the BSO profile, however, identified differential expression of genes related to glycine metabolism and energy metabolism (TPI1). These differential features might be indicative of pre-degenerative blastocysts (IGFBP7) in the AAPH population whereas BSO exposure would select the most viable individuals (TKDP1). Together, these results illustrate how oxidative disruption of pre-attachment development is associated with systematic up-regulation of several metabolic markers. Moreover, it indicates that a better capacity to survive anti-oxidant depletion may allow for the survival of blastocysts with a quieter metabolism after compaction.
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Affiliation(s)
- Gael L M Cagnone
- Département des Sciences Animales, Centre de Recherche en Biologie de la Reproduction, Université Laval, Québec, Canada
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