1
|
Zhang W, Jiang X, Wang M, Zhang Z, Wang N. Origin of the 6/5/6/5 Tetracyclic Cyclopiazonic Acids. Mar Drugs 2024; 22:74. [PMID: 38393045 PMCID: PMC10890092 DOI: 10.3390/md22020074] [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: 01/17/2024] [Revised: 01/29/2024] [Accepted: 01/29/2024] [Indexed: 02/25/2024] Open
Abstract
The natural product α-cyclopiazonic acid (α-CPA) is a very potent Ca2+-ATPase inhibitor. The CPA family of compounds comprise over 80 chemical entities with at least five distinct skeletons. While α-CPA features a canonical 6/5/6/5/5 skeleton, the 6/5/6/5 skeleton is the most prevalent among the CPA family. However, the origin of the unique tetracyclic skeleton remains unknown. The 6/5/6/5-type CPAs may derive from a precursor of acetoacetyl-l-tryptophan (AATrp) generated from a hypothetic thioesterase-like pathway. Alternatively, cleavage of the tetramic acid ring would also result in the formation of the 6/5/6/5 scaffold. Aspergillus oryzae HMP-F28 is a marine sponge-associated filamentous fungus known to produce CPAs that act as primary neurotoxins. To elucidate the origin of this subfamily of CPAs, we performed homologous recombination and genetic engineering experiments on strain HMP-F28. Our results are supportive of the ring cleavage pathway through which the tetracyclic 6/5/6/5-type CPAs are generated from 6/5/6/5/5-type pentacyclic CPAs.
Collapse
Affiliation(s)
- Wenyuan Zhang
- Ocean College, Zhejiang University, Zhoushan 316021, China
| | - Xuejian Jiang
- Ocean College, Zhejiang University, Zhoushan 316021, China
| | - Minjun Wang
- Ocean College, Zhejiang University, Zhoushan 316021, China
| | - Zhizhen Zhang
- Ocean College, Zhejiang University, Zhoushan 316021, China
| | - Nan Wang
- Ocean College, Zhejiang University, Zhoushan 316021, China
- Hainan Institute of Zhejiang University, Sanya 572025, China
| |
Collapse
|
2
|
Hu XQ, Zhang L. Oxidative Regulation of Vascular Ca v1.2 Channels Triggers Vascular Dysfunction in Hypertension-Related Disorders. Antioxidants (Basel) 2022; 11:antiox11122432. [PMID: 36552639 PMCID: PMC9774363 DOI: 10.3390/antiox11122432] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 11/28/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022] Open
Abstract
Blood pressure is determined by cardiac output and peripheral vascular resistance. The L-type voltage-gated Ca2+ (Cav1.2) channel in small arteries and arterioles plays an essential role in regulating Ca2+ influx, vascular resistance, and blood pressure. Hypertension and preeclampsia are characterized by high blood pressure. In addition, diabetes has a high prevalence of hypertension. The etiology of these disorders remains elusive, involving the complex interplay of environmental and genetic factors. Common to these disorders are oxidative stress and vascular dysfunction. Reactive oxygen species (ROS) derived from NADPH oxidases (NOXs) and mitochondria are primary sources of vascular oxidative stress, whereas dysfunction of the Cav1.2 channel confers increased vascular resistance in hypertension. This review will discuss the importance of ROS derived from NOXs and mitochondria in regulating vascular Cav1.2 and potential roles of ROS-mediated Cav1.2 dysfunction in aberrant vascular function in hypertension, diabetes, and preeclampsia.
Collapse
|
3
|
Rauter T, Burgstaller S, Gottschalk B, Ramadani-Muja J, Bischof H, Hay JC, Graier WF, Malli R. ER-to-Golgi Transport in HeLa Cells Displays High Resilience to Ca 2+ and Energy Stresses. Cells 2020; 9:E2311. [PMID: 33080790 PMCID: PMC7603030 DOI: 10.3390/cells9102311] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/09/2020] [Accepted: 10/16/2020] [Indexed: 02/07/2023] Open
Abstract
One third of all human proteins are either transmembrane or soluble secretory proteins that first target the endoplasmic reticulum (ER). These proteins subsequently leave the ER and enter the Golgi apparatus via ER-Golgi intermediate vesicular structures. Live-cell imaging of cargos fused to fluorescent proteins (FPs) enables the high-resolution visualization and characterization of secretory transport processes. Here, we performed fluorescence time-lapse imaging to assess the Ca2+ and energy dependency of ER-to-Golgi transport in living HeLa cells, a cancer cell model which has been well investigated. Our data revealed that ER-to-Golgi transport remained highly efficient in the absence of ATP-generating substrates, despite clear reductions in cytosolic and mitochondrial ATP levels under these energy stress conditions. However, cell treatment with 2-deoxy-D-glucose (2-DG), which severely diminished subcellular ATP levels, abolished ER-to-Golgi transport. Interestingly, while 2-DG elevated cytosolic Ca2+ levels and reduced long-distance movements of glycosylphosphatidylinositol (GPI)-positive vesicles, robust short-term ER Ca2+ mobilizations, which strongly affected the motility of these vesicles, did not considerably impair ER-to-Golgi transport. In summary, we highlight that ER-to-Golgi transport in HeLa cells remains functional despite high energy and Ca2+ stress levels.
Collapse
Affiliation(s)
- Thomas Rauter
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (T.R.); (S.B.); (B.G.); (J.R.-M.); (H.B.); (W.F.G.)
| | - Sandra Burgstaller
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (T.R.); (S.B.); (B.G.); (J.R.-M.); (H.B.); (W.F.G.)
- Interfaculty Institute of Cell Biology, University of Tuebingen, Auf der Morgenstelle 15, 72076 Tuebingen, Germany
| | - Benjamin Gottschalk
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (T.R.); (S.B.); (B.G.); (J.R.-M.); (H.B.); (W.F.G.)
| | - Jeta Ramadani-Muja
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (T.R.); (S.B.); (B.G.); (J.R.-M.); (H.B.); (W.F.G.)
| | - Helmut Bischof
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (T.R.); (S.B.); (B.G.); (J.R.-M.); (H.B.); (W.F.G.)
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, Auf der Morgenstelle 8, 72076 Tuebingen, Germany
| | - Jesse C. Hay
- Division of Biological Sciences and Center for Structural and Functional Neuroscience, The University of Montana, 32 Campus Drive, HS 302A, Missoula, MT 59812-4824, USA;
| | - Wolfgang F. Graier
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (T.R.); (S.B.); (B.G.); (J.R.-M.); (H.B.); (W.F.G.)
- BioTechMed Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Roland Malli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; (T.R.); (S.B.); (B.G.); (J.R.-M.); (H.B.); (W.F.G.)
- BioTechMed Graz, Mozartgasse 12/II, 8010 Graz, Austria
| |
Collapse
|
4
|
Aguayo-Ortiz R, Espinoza-Fonseca LM. Linking Biochemical and Structural States of SERCA: Achievements, Challenges, and New Opportunities. Int J Mol Sci 2020; 21:ijms21114146. [PMID: 32532023 PMCID: PMC7313052 DOI: 10.3390/ijms21114146] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/05/2020] [Accepted: 06/08/2020] [Indexed: 02/07/2023] Open
Abstract
Sarcoendoplasmic reticulum calcium ATPase (SERCA), a member of the P-type ATPase family of ion and lipid pumps, is responsible for the active transport of Ca2+ from the cytoplasm into the sarcoplasmic reticulum lumen of muscle cells, into the endoplasmic reticulum (ER) of non-muscle cells. X-ray crystallography has proven to be an invaluable tool in understanding the structural changes of SERCA, and more than 70 SERCA crystal structures representing major biochemical states (defined by bound ligand) have been deposited in the Protein Data Bank. Consequently, SERCA is one of the best characterized components of the calcium transport machinery in the cell. Emerging approaches in the field, including spectroscopy and molecular simulation, now help integrate and interpret this rich structural information to understand the conformational transitions of SERCA that occur during activation, inhibition, and regulation. In this review, we provide an overview of the crystal structures of SERCA, focusing on identifying metrics that facilitate structure-based categorization of major steps along the catalytic cycle. We examine the integration of crystallographic data with different biophysical approaches and computational methods to link biochemical and structural states of SERCA that are populated in the cell. Finally, we discuss the challenges and new opportunities in the field, including structural elucidation of functionally important and novel regulatory complexes of SERCA, understanding the structural basis of functional divergence among homologous SERCA regulators, and bridging the gap between basic and translational research directed toward therapeutic modulation of SERCA.
Collapse
|
5
|
Peterková L, Kmoníčková E, Ruml T, Rimpelová S. Sarco/Endoplasmic Reticulum Calcium ATPase Inhibitors: Beyond Anticancer Perspective. J Med Chem 2020; 63:1937-1963. [PMID: 32030976 DOI: 10.1021/acs.jmedchem.9b01509] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The sarco/endoplasmic reticulum calcium ATPase (SERCA), which plays a key role in the maintenance of Ca2+ ion homeostasis, is an extensively studied enzyme, the inhibition of which has a considerable impact on cell life and death decision. To date, several SERCA inhibitors have been thoroughly studied and the most notable one, a derivative of the sesquiterpene lactone thapsigargin, is gradually approaching a clinical application. Meanwhile, new compounds with SERCA-inhibiting properties of natural, synthetic, or semisynthetic origin are being discovered and/or developed; some of these might also be suitable for the development of new drugs with improved performance. This review brings an up-to-date comprehensive overview of recently discovered compounds with the potential of SERCA inhibition, discusses their mechanism of action, and highlights their potential clinical applications, such as cancer treatment.
Collapse
Affiliation(s)
- Lucie Peterková
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 5, 166 28, Prague 6, Czech Republic
| | - Eva Kmoníčková
- Faculty of Medicine in Pilsen, Charles University, Alej Svobody 76, 323 00 Pilsen, Czech Republic
| | - Tomáš Ruml
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 5, 166 28, Prague 6, Czech Republic
| | - Silvie Rimpelová
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 5, 166 28, Prague 6, Czech Republic.,Faculty of Medicine in Pilsen, Charles University, Alej Svobody 76, 323 00 Pilsen, Czech Republic
| |
Collapse
|
6
|
Holme JA, Brinchmann BC, Le Ferrec E, Lagadic-Gossmann D, Øvrevik J. Combustion Particle-Induced Changes in Calcium Homeostasis: A Contributing Factor to Vascular Disease? Cardiovasc Toxicol 2020; 19:198-209. [PMID: 30955163 DOI: 10.1007/s12012-019-09518-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Air pollution is the leading environmental risk factor for disease and premature death in the world. This is mainly due to exposure to urban air particle matter (PM), in particular, fine and ultrafine combustion-derived particles (CDP) from traffic-related air pollution. PM and CDP, including particles from diesel exhaust (DEP), and cigarette smoke have been linked to various cardiovascular diseases (CVDs) including atherosclerosis, but the underlying cellular mechanisms remain unclear. Moreover, CDP typically consist of carbon cores with a complex mixture of organic chemicals such as polycyclic aromatic hydrocarbons (PAHs) adhered. The relative contribution of the carbon core and adhered soluble components to cardiovascular effects of CDP is still a matter of discussion. In the present review, we summarize evidence showing that CDP affects intracellular calcium regulation, and argue that CDP-induced impairment of normal calcium control may be a critical cellular event through which CDP exposure contributes to development or exacerbation of cardiovascular disease. Furthermore, we highlight in vitro research suggesting that adhered organic chemicals such as PAHs may be key drivers of these responses. CDP, extractable organic material from CDP (CDP-EOM), and PAHs may increase intracellular calcium levels by interacting with calcium channels like transient receptor potential (TRP) channels, and receptors such as G protein-coupled receptors (GPCR; e.g., beta-adrenergic receptors [βAR] and protease-activated receptor 2 [PAR-2]) and the aryl hydrocarbon receptor (AhR). Clarifying a possible role of calcium signaling and mechanisms involved may increase our understanding of how air pollution contributes to CVD.
Collapse
Affiliation(s)
- Jørn A Holme
- Department of Air Pollution and Noise, Division of Infection Control, Environment and Health, Norwegian Institute of Public Health, PO Box 4404, Nydalen, 0403, Oslo, Norway.
| | - Bendik C Brinchmann
- Department of Air Pollution and Noise, Division of Infection Control, Environment and Health, Norwegian Institute of Public Health, PO Box 4404, Nydalen, 0403, Oslo, Norway
| | - Eric Le Ferrec
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé environnement et travail) - UMR_S 1085, 35000, Rennes, France
| | - Dominique Lagadic-Gossmann
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé environnement et travail) - UMR_S 1085, 35000, Rennes, France
| | - Johan Øvrevik
- Department of Air Pollution and Noise, Division of Infection Control, Environment and Health, Norwegian Institute of Public Health, PO Box 4404, Nydalen, 0403, Oslo, Norway.
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway.
| |
Collapse
|
7
|
García-Casas P, Arias-Del-Val J, Alvarez-Illera P, Fonteriz RI, Montero M, Alvarez J. Inhibition of Sarco-Endoplasmic Reticulum Ca 2+ ATPase Extends the Lifespan in C. elegans Worms. Front Pharmacol 2018; 9:669. [PMID: 29988547 PMCID: PMC6026643 DOI: 10.3389/fphar.2018.00669] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 06/04/2018] [Indexed: 12/20/2022] Open
Abstract
The sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) refills the endoplasmic reticulum (ER) with Ca2+ up to the millimolar range and is therefore the main controller of the ER [Ca2+] level ([Ca2+]ER), which has a key role in the modulation of cytosolic Ca2+ signaling and ER-mitochondria Ca2+ transfer. Given that both cytosolic and mitochondrial Ca2+ dynamics strongly interplay with energy metabolism and nutrient-sensitive pathways, both of them involved in the aging process, we have studied the effect of SERCA inhibitors on lifespan in C. elegans. We have used thapsigargin and 2,5-Di-tert-butylhydroquinone (2,5-BHQ) as SERCA inhibitors, and the inactive analog 2,6-Di-tert-butylhydroquinone (2,6-BHQ) as a control for 2,5-BHQ. Every drug was administered to the worms either directly in the agar or via an inclusion compound with γ-cyclodextrin. The results show that 2,6-BHQ produced a small but significant increase in survival, perhaps because of its antioxidant properties. However, 2,5-BHQ produced in all the conditions a much higher increase in lifespan, and the potent and specific SERCA inhibitor thapsigargin also extended the lifespan. The effects of 2,5-BHQ and thapsigargin had a bell-shaped concentration dependence, with a maximum effect at a certain dose and smaller or even toxic effects at higher concentrations. Our data show therefore that submaximal inhibition of SERCA pumps has a pro-longevity effect, suggesting that Ca2+ signaling plays an important role in the aging process and that it could be a promising novel target pathway to act on aging.
Collapse
Affiliation(s)
- Paloma García-Casas
- Department of Biochemistry and Molecular Biology and Physiology, Institute of Biology and Molecular Genetics (IBGM), Faculty of Medicine, University of Valladolid - CSIC, Valladolid, Spain
| | - Jessica Arias-Del-Val
- Department of Biochemistry and Molecular Biology and Physiology, Institute of Biology and Molecular Genetics (IBGM), Faculty of Medicine, University of Valladolid - CSIC, Valladolid, Spain
| | - Pilar Alvarez-Illera
- Department of Biochemistry and Molecular Biology and Physiology, Institute of Biology and Molecular Genetics (IBGM), Faculty of Medicine, University of Valladolid - CSIC, Valladolid, Spain
| | - Rosalba I Fonteriz
- Department of Biochemistry and Molecular Biology and Physiology, Institute of Biology and Molecular Genetics (IBGM), Faculty of Medicine, University of Valladolid - CSIC, Valladolid, Spain
| | - Mayte Montero
- Department of Biochemistry and Molecular Biology and Physiology, Institute of Biology and Molecular Genetics (IBGM), Faculty of Medicine, University of Valladolid - CSIC, Valladolid, Spain
| | - Javier Alvarez
- Department of Biochemistry and Molecular Biology and Physiology, Institute of Biology and Molecular Genetics (IBGM), Faculty of Medicine, University of Valladolid - CSIC, Valladolid, Spain
| |
Collapse
|
8
|
Berkowitz BA. Oxidative stress measured in vivo without an exogenous contrast agent using QUEST MRI. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 291:94-100. [PMID: 29705036 PMCID: PMC5963509 DOI: 10.1016/j.jmr.2018.01.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 01/09/2018] [Accepted: 01/24/2018] [Indexed: 05/10/2023]
Abstract
Decades of experimental studies have implicated excessive generation of reactive oxygen species (ROS) in the decline of tissue function during normal aging, and as a pathogenic factor in a vast array of fatal or debilitating morbidities. This massive body of work has important clinical implications since many antioxidants are FDA approved, readily cross blood-tissue barriers, and are effective at improving disease outcomes. Yet, the potential benefits of antioxidants have remained largely unrealized in patients because conventional methods cannot determine the dose, timing, and drug combinations to be used in clinical trials to localize and decrease oxidative stress. To address this major problem and improve translational success, new methods are urgently needed that non-invasively measure the same ROS biomarker both in animal models and patients with high spatial resolution. Here, we summarize a transformative solution based on a novel method: QUEnch-assiSTed MRI (QUEST MRI). The QUEST MRI index is a significant antioxidant-induced improvement in pathophysiology, or a reduction in 1/T1 (i.e., R1). The latter form of QUEST MRI provides a unique measure of uncontrolled production of endogenous, paramagnetic reactive oxygen species (ROS). QUEST MRI results to-date have been validated by gold standard oxidative stress assays. QUEST MRI has high translational potential because it does not use an exogenous contrast agent and requires only standard MRI equipment. Summarizing, QUEST MRI is a powerful non-invasive approach with unprecedented potential for (i) bridging antioxidant treatment in animal models and patients, (ii) identifying tissue subregions exhibiting oxidative stress, and (iii) coupling oxidative stress localization with behavioral dysfunction, disease pathology, and genetic vulnerabilities to serve as a marker of susceptibility.
Collapse
Affiliation(s)
- Bruce A Berkowitz
- Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48201, United States; Department of Ophthalmology, Wayne State University School of Medicine, Detroit, MI 48201, United States.
| |
Collapse
|
9
|
Singh P, Singh UP, Peddinti RK. PTSA–catalyzed functionalization of hydroquinones with benzhydryl alcohols in water. Tetrahedron Lett 2017. [DOI: 10.1016/j.tetlet.2017.06.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
|
10
|
Saponara S, Durante M, Spiga O, Mugnai P, Sgaragli G, Huong TT, Khanh PN, Son NT, Cuong NM, Fusi F. Functional, electrophysiological and molecular docking analysis of the modulation of Cav 1.2 channels in rat vascular myocytes by murrayafoline A. Br J Pharmacol 2015; 173:292-304. [PMID: 26493241 DOI: 10.1111/bph.13369] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 10/01/2015] [Accepted: 10/10/2015] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE The carbazole alkaloid murrayafoline A (MuA) enhances contractility and the Ca(2+) currents carried by the Cav 1.2 channels [ICa1.2 ] of rat cardiomyocytes. As only few drugs stimulate ICa1.2 , this study was designed to analyse the effects of MuA on vascular Cav 1.2 channels. EXPERIMENTAL APPROACH Vascular activity was assessed on rat aorta rings mounted in organ baths. Cav 1.2 Ba(2+) current [IBa1.2 ] was recorded in single rat aorta and tail artery myocytes by the patch-clamp technique. Docking at a 3D model of the rat, α1c central pore subunit of the Cav 1.2 channel was simulated in silico. KEY RESULTS In rat aorta rings MuA, at concentrations ≤14.2 μM, increased 30 mM K(+) -induced tone and shifted the concentration-response curve to K(+) to the left. Conversely, at concentrations >14.2 μM, it relaxed high K(+) depolarized rings and antagonized Bay K 8644-induced contraction. In single myocytes, MuA stimulated IBa1.2 in a concentration-dependent, bell-shaped manner; stimulation was stable, incompletely reversible upon drug washout and accompanied by a leftward shift of the voltage-dependent activation curve. MuA docked at the α1C subunit central pore differently from nifedipine and Bay K 8644, although apparently interacting with the same amino acids of the pocket. Neither Bay K 8644-induced stimulation nor nifedipine-induced block of IBa1.2 was modified by MuA. CONCLUSIONS AND IMPLICATIONS Murrayafoline A is a naturally occurring vasoactive agent able to modulate Cav 1.2 channels and dock at the α1C subunit central pore in a manner that differed from that of dihydropyridines.
Collapse
Affiliation(s)
- S Saponara
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Siena, Italy
| | - M Durante
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Siena, Italy
| | - O Spiga
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Siena, Italy
| | - P Mugnai
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Siena, Italy
| | - G Sgaragli
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Siena, Italy
| | - T T Huong
- Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - P N Khanh
- Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - N T Son
- Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - N M Cuong
- Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - F Fusi
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Siena, Italy
| |
Collapse
|
11
|
Berkowitz BA, Bissig D, Roberts R. MRI of rod cell compartment-specific function in disease and treatment in vivo. Prog Retin Eye Res 2015; 51:90-106. [PMID: 26344734 DOI: 10.1016/j.preteyeres.2015.09.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/26/2015] [Accepted: 09/01/2015] [Indexed: 10/23/2022]
Abstract
Rod cell oxidative stress is a major pathogenic factor in retinal disease, such as diabetic retinopathy (DR) and retinitis pigmentosa (RP). Personalized, non-destructive, and targeted treatment for these diseases remains elusive since current imaging methods cannot analytically measure treatment efficacy against rod cell compartment-specific oxidative stress in vivo. Over the last decade, novel MRI-based approaches that address this technology gap have been developed. This review summarizes progress in the development of MRI since 2006 that enables earlier evaluation of the impact of disease on rod cell compartment-specific function and the efficacy of anti-oxidant treatment than is currently possible with other methods. Most of the new assays of rod cell compartment-specific function are based on endogenous contrast mechanisms, and this is expected to facilitate their translation into patients with DR and RP, and other oxidative stress-based retinal diseases.
Collapse
Affiliation(s)
- Bruce A Berkowitz
- Dept. of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI, USA; Dept. Of Ophthalmology, Wayne State University School of Medicine, Detroit, MI, USA.
| | - David Bissig
- Dept. of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Robin Roberts
- Dept. Of Ophthalmology, Wayne State University School of Medicine, Detroit, MI, USA
| |
Collapse
|
12
|
Spinelli D, Budriesi R, Cosimelli B, Severi E, Micucci M, Baroni M, Fusi F, Ioan P, Cross S, Frosini M, Saponara S, Matucci R, Rosano C, Viale M, Chiarini A, Carosati E. Playing with opening and closing of heterocycles: using the cusmano-ruccia reaction to develop a novel class of oxadiazolothiazinones, active as calcium channel modulators and P-glycoprotein inhibitors. Molecules 2014; 19:16543-72. [PMID: 25317581 PMCID: PMC6271282 DOI: 10.3390/molecules191016543] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 08/15/2014] [Accepted: 09/04/2014] [Indexed: 11/23/2022] Open
Abstract
As a result of the ring-into-ring conversion of nitrosoimidazole derivatives, we obtained a molecular scaffold that, when properly decorated, is able to decrease inotropy by blocking L-type calcium channels. Previously, we used this scaffold to develop a quantitative structure-activity relationship (QSAR) model, and we used the most potent oxadiazolothiazinone as a template for ligand-based virtual screening. Here, we enlarge the diversity of chemical decorations, present the synthesis and in vitro data for 11 new derivatives, and develop a new 3D-QSAR model with recent in silico techniques. We observed a key role played by the oxadiazolone moiety: given the presence of positively charged calcium ions in the transmembrane channel protein, we hypothesize the formation of a ternary complex between the oxadiazolothiazinone, the Ca2+ ion and the protein. We have supported this hypothesis by means of pharmacophore generation and through the docking of the pharmacophore into a homology model of the protein. We also studied with docking experiments the interaction with a homology model of P-glycoprotein, which is inhibited by this series of molecules, and provided further evidence toward the relevance of this scaffold in biological interactions.
Collapse
Affiliation(s)
- Domenico Spinelli
- Dipartimento di Chimica "G. Ciamician", Alma Mater Studiorum-Università di Bologna, Via F. Selmi 2, Bologna 40126, Italy.
| | - Roberta Budriesi
- Dipartimento di Farmacia e Biotecnologie, Alma Mater Studiorum-Università di Bologna, Via Belmeloro 6, Bologna 40126, Italy.
| | - Barbara Cosimelli
- Dipartimento di Farmacia, Università di Napoli "Federico II", Via D. Montesano 49, Napoli 80131, Italy.
| | - Elda Severi
- Dipartimento di Farmacia, Università di Napoli "Federico II", Via D. Montesano 49, Napoli 80131, Italy.
| | - Matteo Micucci
- Dipartimento di Farmacia e Biotecnologie, Alma Mater Studiorum-Università di Bologna, Via Belmeloro 6, Bologna 40126, Italy.
| | - Massimo Baroni
- Molecular Discovery Ltd., 215 Marsh Road, Pinner, Middlesex HA5 5NE, UK.
| | - Fabio Fusi
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Via A. Moro 2, Siena 53100, Italy.
| | - Pierfranco Ioan
- Dipartimento di Farmacia e Biotecnologie, Alma Mater Studiorum-Università di Bologna, Via Belmeloro 6, Bologna 40126, Italy.
| | - Simon Cross
- Molecular Discovery Ltd., 215 Marsh Road, Pinner, Middlesex HA5 5NE, UK.
| | - Maria Frosini
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Via A. Moro 2, Siena 53100, Italy.
| | - Simona Saponara
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Via A. Moro 2, Siena 53100, Italy.
| | - Rosanna Matucci
- Dipartimento di Neuroscienze, Area del Farmaco e Salute del Bambino (NEUROFARBA) Viale Pieraccini 6, Firenze 50139, Italy.
| | - Camillo Rosano
- IRCCS Azienda Ospedaliera Universitaria San Martino-IST Istituto Nazionale per la Ricerca sul Cancro, U.O.S. Biopolimeri e Proteomica, L.go R. Benzi, 10, Genova 16132, Italy.
| | - Maurizio Viale
- IRCCS Azienda Ospedaliera Universitaria San Martino-IST Istituto Nazionale per la Ricerca sul Cancro, U.O.C. Bioterapie, L.go R. Benzi, 10, Genova 16132, Italy.
| | - Alberto Chiarini
- Dipartimento di Farmacia e Biotecnologie, Alma Mater Studiorum-Università di Bologna, Via Belmeloro 6, Bologna 40126, Italy.
| | - Emanuele Carosati
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 10, Perugia 06123, Italy.
| |
Collapse
|
13
|
Cuong NM, Khanh PN, Huyen PT, Duc HV, Huong TT, Ha VT, Durante M, Sgaragli G, Fusi F. Vascular L-type Ca²⁺ channel blocking activity of sulfur-containing indole alkaloids from Glycosmis petelotii. JOURNAL OF NATURAL PRODUCTS 2014; 77:1586-1593. [PMID: 24949913 DOI: 10.1021/np500076v] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In the search for novel natural compounds endowed with potential antihypertensive activity, a new sulfur-containing indole alkaloid, N-demethylglypetelotine (2), and its known analogue glypetelotine (1), were isolated from the leaves of Glycosmis petelotii. Their structures were established on the basis of spectroscopic evidence. The two alkaloids were assessed for vasorelaxing activity on rat aorta rings and for L-type Ba(2+) current [I(Ba(L))] blocking activity on single myocytes isolated from rat tail artery. Both glypetelotine and N-demethylglypetelotine inhibited phenylephrine-induced contraction with IC50 values of 20 and 50 μM, respectively. The presence of endothelium did not modify their spasmolytic effect. Neither glypetelotine nor N-demethylglypetelotine affected Ca(2+) release from the sarcoplasmic reticulum induced by phenylephrine. The spasmolytic effect of glypetelotine increased with membrane depolarization. In the presence of 60 mM K(+), both compounds inhibited, in a concentration-dependent manner, the contraction induced by cumulative addition of Ca(2+), this inhibition being inversely related to Ca(2+) concentration. Glypetelotine and, less efficiently N-demethylglypetelotine, inhibited I(Ba(L)), the former compound also affecting I(Ba(L)) kinetics. In conclusion, glypetelotine is a novel vasorelaxing agent which antagonizes L-type Ca(2+) channels.
Collapse
Affiliation(s)
- Nguyen Manh Cuong
- Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology , 18 Hoang Quoc Viet Street, 122100 Cau Giay, Hanoi Vietnam
| | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Mugnai P, Durante M, Sgaragli G, Saponara S, Paliuri G, Bova S, Fusi F. L-type Ca(2+) channel current characteristics are preserved in rat tail artery myocytes after one-day storage. Acta Physiol (Oxf) 2014; 211:334-45. [PMID: 24666564 DOI: 10.1111/apha.12282] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/04/2013] [Accepted: 03/21/2014] [Indexed: 12/14/2022]
Abstract
AIM To develop a cheap and simple method of storing for 24-h vascular tissue and single myocytes while preserving therein the biophysical and pharmacological characteristics of L-type Ca(2+) channels and contractile activity. METHODS Rings or vascular smooth muscle cells obtained from the rat tail main artery were used either freshly (R0h and VSMC0h) or stored for 24 h (R24h and VSMC24h) at 4 °C, to record whole-cell L-type Ca(2+) currents (IC a(L) ) or measure contractile responses. RESULTS R0h/VSMC0h and R24h/VSMC24h comparably contracted when stimulated with phenylephrine, high KCl or ATP. In both VSMC0h and VSMC24h, IC a(L) was identified and characterized as a stable inward current for at least 35 min; IC a(L) was comparably inhibited by the Ca(2+) antagonists nifedipine, verapamil and diltiazem and increased by the Ca(2+) channel agonist (S)-(-)-Bay K 8644; current density and current-voltage relationships were similar; at more hyperpolarized holding potentials, IC a(L) intensity increased comparably; nifedipine shifted the steady-state inactivation curve towards more negative potentials, while verapamil blocked IC a(L) in a frequency-dependent manner and slowed down the rate of recovery from inactivation in a comparable way. CONCLUSION Findings show that smooth muscle contractile activity and the biophysical and pharmacological features of L-type Ca(2+) channels are similar in VSMC24h and VSMC0h. The fact that reproducible results were obtained in vascular myocytes up to 24 h after dissociation may facilitate vascular smooth muscle cell investigation by increasing throughput and reducing the number of animals required.
Collapse
Affiliation(s)
- P. Mugnai
- Dipartimento di Scienze della Vita; Università di Siena; Siena Italy
| | - M. Durante
- Dipartimento di Scienze della Vita; Università di Siena; Siena Italy
| | - G. Sgaragli
- Dipartimento di Scienze della Vita; Università di Siena; Siena Italy
| | - S. Saponara
- Dipartimento di Scienze della Vita; Università di Siena; Siena Italy
| | - G. Paliuri
- Dipartimento di Scienze del Farmaco; Università degli Studi di Padova; Padova Italy
| | - S. Bova
- Dipartimento di Scienze del Farmaco; Università degli Studi di Padova; Padova Italy
| | - F. Fusi
- Dipartimento di Scienze della Vita; Università di Siena; Siena Italy
| |
Collapse
|
15
|
Pharmacological correction of gating defects in the voltage-gated Ca(v)2.1 Ca²⁺ channel due to a familial hemiplegic migraine mutation. Neuron 2014; 81:91-102. [PMID: 24411734 DOI: 10.1016/j.neuron.2013.10.056] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2013] [Indexed: 11/20/2022]
Abstract
Voltage-gated ion channels exhibit complex properties, which can be targeted in pharmacological therapies for disease. Here, we report that the pro-oxidant, tert-butyl dihydroquinone (BHQ), modulates Ca(v)2.1 Ca²⁺ channels in ways that oppose defects in channel gating and synaptic transmission resulting from a familial hemiplegic migraine mutation (S218L). BHQ slows deactivation, inhibits voltage-dependent activation, and potentiates Ca²⁺-dependent facilitation of Ca(v)2.1 channels in transfected HEK293T cells. These actions of BHQ help offset the gain of function and reduced Ca²⁺-dependent facilitation of Ca(v)2.1 channels with the S218L mutation. Transgenic expression of the mutant channels at the Drosophila neuromuscular junction causes abnormally elevated evoked postsynaptic potentials and impaired synaptic plasticity, which are largely restored to the wild-type phenotypes by BHQ. Our results reveal a mechanism by which a Ca(v)2.1 gating modifier can ameliorate defects associated with a disease-causing mutation in Ca(v)2.1.
Collapse
|
16
|
Núñez-Santana FL, Oh MM, Antion MD, Lee A, Hell JW, Disterhoft JF. Surface L-type Ca2+ channel expression levels are increased in aged hippocampus. Aging Cell 2014; 13:111-20. [PMID: 24033980 PMCID: PMC3947046 DOI: 10.1111/acel.12157] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2013] [Indexed: 12/30/2022] Open
Abstract
Age-related increase in L-type Ca2+ channel (LTCC) expression in hippocampal pyramidal neurons has been hypothesized to underlie the increased Ca2+ influx and subsequent reduced intrinsic neuronal excitability of these neurons that lead to age-related cognitive deficits. Here, using specific antibodies against Cav1.2 and Cav1.3 subunits of LTCCs, we systematically re-examined the expression of these proteins in the hippocampus from young (3 to 4 month old) and aged (30 to 32 month old) F344xBN rats. Western blot analysis of the total expression levels revealed significant reductions in both Cav1.2 and Cav1.3 subunits from all three major hippocampal regions of aged rats. Despite the decreases in total expression levels, surface biotinylation experiments revealed significantly higher proportion of expression on the plasma membrane of Cav1.2 in the CA1 and CA3 regions and of Cav1.3 in the CA3 region from aged rats. Furthermore, the surface biotinylation results were supported by immunohistochemical analysis that revealed significant increases in Cav1.2 immunoreactivity in the CA1 and CA3 regions of aged hippocampal pyramidal neurons. In addition, we found a significant increase in the level of phosphorylated Cav1.2 on the plasma membrane in the dentate gyrus of aged rats. Taken together, our present findings strongly suggest that age-related cognitive deficits cannot be attributed to a global change in L-type channel expression nor to the level of phosphorylation of Cav1.2 on the plasma membrane of hippocampal neurons. Rather, increased expression and density of LTCCs on the plasma membrane may underlie the age-related increase in L-type Ca2+ channel activity in CA1 pyramidal neurons.
Collapse
Affiliation(s)
- Félix Luis Núñez-Santana
- Department of Physiology; Feinberg School of Medicine; Northwestern University; Chicago IL 60611 USA
| | - Myongsoo Matthew Oh
- Department of Physiology; Feinberg School of Medicine; Northwestern University; Chicago IL 60611 USA
| | - Marcia Diana Antion
- Department of Physiology; Feinberg School of Medicine; Northwestern University; Chicago IL 60611 USA
| | - Amy Lee
- Departments of Molecular Physiology and Biophysics, Otolaryngology-Head and Neck Surgery, and Neurology; University of Iowa; Iowa City IA 52242 USA
| | | | - John Francis Disterhoft
- Department of Physiology; Feinberg School of Medicine; Northwestern University; Chicago IL 60611 USA
| |
Collapse
|
17
|
Fusi F, Durante M, Sgaragli G, Cuong NM, Dung PTP, Nam NH. 2-Aryl- and 2-amido-benzothiazoles as multifunctional vasodilators on rat artery preparations. Eur J Pharmacol 2013; 714:178-87. [PMID: 23751511 DOI: 10.1016/j.ejphar.2013.05.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 05/14/2013] [Accepted: 05/29/2013] [Indexed: 10/26/2022]
Abstract
The neuroprotective agent riluzole [2-amino-6-(trifluoromethoxy)benzothiazole] has been shown to antagonize neuronal high-voltage activated Ca(2+) currents. In the search for novel scaffolds leading to potential antihypertensive agents, a series of 2-aryl- and 2-amido-benzothiazoles (HUP) were assessed for their vasorelaxing property on rat aorta rings and for their L-type Ba(2+) currents [I(Ba(L))] blocking activity on single myocytes isolated from the rat tail artery. HUP5 and HUP30, the most potent of the series, inhibited phenylephrine-induced contraction with IC₅₀ values in the range 3-6 µM. The presence of endothelium did not modify their spasmolytic activity. Both HUP5 and HUP30 increased tissue levels of cGMP and shifted to the left the concentration-response curve to sodium nitroprusside. In rings precontracted by phenylephrine, tetraethylammonium or 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one (ODQ) shifted to the right the concentration-relaxation curves of HUP5 and HUP30. The antispasmodic effect of HUP5 and HUP30 was more marked on rings stimulated with 25/30 mM than with 60 mM K(+). HUP5 and HUP30 antagonized both extracellular Ca(2+) influx and Ca(2+) mobilization from intracellular stores in response to phenylephrine: this effect was not modified by the presence of ODQ. I(Ba(L)) was partly inhibited by HUP5 and blocked by HUP30 in a concentration-dependent as well as ODQ-independent manner. In conclusion, HUP5 and HUP30 are vasorelaxing agents that stimulate soluble guanylyl cyclase, activate K(+) channels, and block extracellular Ca(2+) influx. The present benzothiazole derivatives form a novel class of multifunctional vasodilators which may give rise to effective antihypertensive agents.
Collapse
Affiliation(s)
- Fabio Fusi
- Dipartimento di Scienze della Vita, Università di Siena, via A. Moro 2, 53100 Siena, Italy.
| | | | | | | | | | | |
Collapse
|
18
|
Saponara S, Fusi F, Sgaragli G, Cavalli M, Hopkins B, Bova S. Effects of commonly used protein kinase inhibitors on vascular contraction and L-type Ca(2+) current. Biochem Pharmacol 2012; 84:1055-61. [PMID: 22884855 DOI: 10.1016/j.bcp.2012.07.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 07/24/2012] [Accepted: 07/25/2012] [Indexed: 10/28/2022]
Abstract
Regulation of smooth muscle contraction is driven by a number of protein kinases: the evidence for this often originates from studies that investigate the effects of extracellularly added specific protein kinase inhibitors. Six compounds, thought to be selective inhibitors of various kinases, were analysed for their effects on vascular L-type Ca(2+) channels because this potential subsidiary activity could strongly influence our understanding of the pathways involved in smooth muscle contraction. Whole-cell L-type Ba(2+) currents [I(Ba(L))] were recorded in single myocytes, and contractile responses were measured from endothelium-denuded rings taken from the rat tail artery. Although ML-7, ML-9, and wortmannin (MLCK inhibitors), HA-1077 and Y-27632 (Rho-associated kinase inhibitors), and GF-109203X (PKC inhibitor) relaxed rings pre-contracted with high KCl in a concentration-dependent manner, their effect on I(Ba(L)) intensity was surprisingly variable. Wortmannin showed negligible effects while HA-1077 and Y-27632 were ineffective. I(Ba(L)) was partly inhibited by GF-109203X and blocked by ML-7 and ML-9 in a concentration-dependent manner, with the blockade by ML-7 being voltage-dependent. Whilst ML-7, ML-9, and GF-109203X sped up the inactivation kinetics of I(Ba(L)), GF-109203X did not modify ML-7- or ML-9-induced effects, with both intensity and kinetics of the current remaining unchanged. In contrast, application of Bay K 8644 on myocytes pre-treated with ML-7 or ML-9 raised I(Ba(L)) beyond control values. In conclusion, ML-7 and ML-9 inhibit L-type Ca(2+) channels via a mechanism independent of MLCK, PKC or Rho kinase activities, and as such caution should be used in employing these agents to elucidate the role of kinases in smooth muscle contraction.
Collapse
Affiliation(s)
- Simona Saponara
- Dipartimento di Neuroscienze, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy
| | | | | | | | | | | |
Collapse
|
19
|
Mechanism of osthole inhibition of vascular Cav1.2 current. Eur J Pharmacol 2012; 680:22-7. [DOI: 10.1016/j.ejphar.2012.01.038] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Revised: 01/23/2012] [Accepted: 01/28/2012] [Indexed: 11/22/2022]
|
20
|
Saponara S, Carosati E, Mugnai P, Sgaragli G, Fusi F. The flavonoid scaffold as a template for the design of modulators of the vascular Ca(v) 1.2 channels. Br J Pharmacol 2012; 164:1684-97. [PMID: 21557738 DOI: 10.1111/j.1476-5381.2011.01476.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Previous studies have pointed to the plant flavonoids myricetin and quercetin as two structurally related stimulators of vascular Ca(v) 1.2 channel current (I(Ca1.2) ). Here we have tested the proposition that the flavonoid structure confers the ability to modulate Ca(v) 1.2 channels. EXPERIMENTAL APPROACH Twenty-four flavonoids were analysed for their effects on I(Ca1.2) in rat tail artery myocytes, using the whole-cell patch-clamp method. KEY RESULTS Most of the flavonoids stimulated or inhibited I(Ca1.2) in a concentration- and voltage-dependent manner with EC(50) values ranging between 4.4 µM (kaempferol) and 16.0 µM (myricetin) for the stimulators and IC(50) values between 13.4 µM (galangin) and 100 µM [(±)-naringenin] for the inhibitors. Key structural requirements for I(Ca1.2) stimulatory activity were the double bond between C2 and C3 and the hydroxylation pattern on the flavonoid scaffold, the latter also determining the molecular charge, as shown by molecular modelling techniques. Absence of OH groups in the B ring was key in I(Ca1.2) inhibition. The functional interaction between quercetin and either the stimulator myricetin or the antagonists resokaempferol, crysin, genistein, and 5,7,2'-trihydroxyflavone revealed that quercetin expressed the highest apparent affinity, in the low µM range, for Ca(v) 1.2 channels. Neither protein tyrosine kinase nor protein kinase Cα were involved in quercetin-induced stimulation of I(Ca1.2). CONCLUSIONS AND IMPLICATIONS Quercetin-like plant flavonoids were active on vascular Ca(v)1.2 channels. Thus, the flavonoid scaffold may be a template for the design of novel modulators of vascular smooth muscle Ca(v)1.2 channels, valuable for the treatment of hypertension and stroke.
Collapse
Affiliation(s)
- S Saponara
- Dipartimento di Neuroscienze, Università degli Studi di Siena, Siena, Italy
| | | | | | | | | |
Collapse
|
21
|
Saponara S, Gorelli B, Tzankova V, Martelli C, Teodori E, Sgaragli G, Fusi F. The novel potent multidrug resistance inhibitors N,N-bis(cyclohexanol)amine aryl esters are devoid of vascular effects. Pharmacology 2011; 88:137-41. [PMID: 21921667 DOI: 10.1159/000330452] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 06/16/2011] [Indexed: 11/19/2022]
Abstract
The aim of this study was to investigate the effects of the four isomers (3a, 3b, 3c and 3d) of a novel multidrug resistance-reverting agent - 3,4,5-trimethoxybenzoic acid 4-(methyl-{4-[3-(3,4,5-trimethoxyphenyl)acryloyloxy]cyclohexyl}amino)cyclohexyl ester - on vascular functions in vitro. A comparison of their mechanical and electrophysiological actions in rat aorta rings and single rat tail artery myocytes, respectively, was performed. In rat aorta rings, 3a-d antagonized both 60 mmol/l K(+)- and phenylephrine-induced contraction in a concentration-dependent manner, with maximal relaxation values averaging 50% of controls, 3d being the most effective of the series. The vasorelaxing effect was similar either in presence or absence of intact endothelium. In rat tail artery myocytes, out of the four isomers, only 3a consistently inhibited Ba(2+) current through Ca(v)1.2 channels. Our results provide functional evidence that 3a-d are weak vasorelaxing agents, although at concentrations much higher than those effective for multidrug resistance reversion in cancer cells.
Collapse
Affiliation(s)
- Simona Saponara
- Dipartimento di Neuroscienze, Università degli Studi di Siena, Siena, Italy.
| | | | | | | | | | | | | |
Collapse
|
22
|
Curine, a bisbenzylisoquinoline alkaloid, blocks L-type Ca²⁺ channels and decreases intracellular Ca²⁺ transients in A7r5 cells. Eur J Pharmacol 2011; 669:100-7. [PMID: 21872583 DOI: 10.1016/j.ejphar.2011.07.044] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 07/13/2011] [Accepted: 07/30/2011] [Indexed: 12/14/2022]
Abstract
Curine is a novel bisbenzylisoquinoline alkaloid that has previously been reported as a vasodilator. The underlying mechanism(s) of the vasodilator effect of curine remains to be characterized. In this study, we investigated the cellular mechanism that is responsible for the vasodilator effect of curine in the rat aorta. The vasorelaxant activity of curine was recorded using a myograph. Ca(2+) currents in A7r5 cells were measured using the whole-cell patch-clamp technique. Intracellular Ca(2+) transients were determined using confocal microscopy. In a concentration-dependent manner, curine inhibited contractions elicited by high extracellular K(+) and Bay K8644 in the rat aorta and reduced the rise in the intracellular Ca(2+) concentration induced by membrane depolarization in response to an increase in extracellular K(+) concentration in vascular smooth muscle cells. Moreover, curine decreased the peak amplitude of L-type Ca(2+) currents (I(Ca,L)) in a concentration-dependent manner without changing the characteristics of the current density vs. voltage relationship and the steady-state activation of I(Ca,L). Furthermore, curine shifted the steady-state inactivation curve of I(Ca,L) toward more hyperpolarized membrane potentials. None of the following modified the effect of curine on I(Ca,L) amplitude: 3-isobutyl-1-methylxanthine, an inhibitor of phosphodiesterases; dibutyryl cyclic AMP, an activator of protein kinase A (PKA); or 8-Br-cyclic GMP, an activator of protein kinase G (PKG). Our results showed that curine inhibited the L-type voltage-dependent Ca(2+) current in rat aorta smooth muscle cells, which caused a decrease in intracellular global Ca(2+) transients that led to vasorelaxation.
Collapse
|
23
|
Fusi F, Cavalli M, Mulholland D, Crouch N, Coombes P, Dawson G, Bova S, Sgaragli G, Saponara S. Cardamonin is a bifunctional vasodilator that inhibits Ca(v)1.2 current and stimulates K(Ca)1.1 current in rat tail artery myocytes. J Pharmacol Exp Ther 2009; 332:531-40. [PMID: 19923439 DOI: 10.1124/jpet.109.161265] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
An in-depth analysis of the effects of cardamonin, 2',4'-dihydroxy-6'-methoxychalcone, on rat tail artery preparations was performed by means of whole-cell patch-clamp recordings of Ca(v)1.2 Ca(2+) [I(Ca(L))] or Ba(2+) [I(Ba(L))] current as well as K(Ca)1.1 currents in single myocytes and by measuring contractile responses in endothelium-denuded isolated rings. At a holding potential (V(h)) of -80 mV, cardamonin decreased both I(Ba(L)) and I(Ca(L)) in a concentration-dependent manner with similar pIC(50) values. The maximum of the I(Ba(L))-voltage relationship was shifted by 10 mV in the hyperpolarizing direction, but threshold remained unaffected. Cardamonin modified both the activation and the inactivation kinetics of I(Ba(L)) and shifted the voltage dependence of both inactivation and activation curves to more negative potentials by 19 and 7 mV, respectively, thus markedly decreasing the Ba(2+) window current. Block of I(Ba(L)) was frequency-dependent, and rate of recovery from inactivation was slowed. Cardamonin increased K(Ca)1.1 currents in a concentration-dependent manner; this stimulation was iberiotoxin- and BAPTA [1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid]-sensitive. On the contrary, iberiotoxin did not modify cardamonin-induced relaxation of rings precontracted either with phenylephrine or with (S)-(-)-methyl-1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)pyridine-5-carboxylate [(S)-(-)-Bay K 8644]. The overall effects of cardamonin were incompletely reversed by washout. In conclusion, cardamonin is a naturally occurring, bifunctional vasodilator that, by simultaneously inhibiting I(Ca(L)) and stimulating K(Ca)1.1 current, may represent a scaffold for the design of novel drugs of potential interest for treatment of systemic hypertension.
Collapse
Affiliation(s)
- Fabio Fusi
- Dipartimento di Neuroscienze, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy.
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Carosati E, Budriesi R, Ioan P, Cruciani G, Fusi F, Frosini M, Saponara S, Gasparrini F, Ciogli A, Villani C, Stephens PJ, Devlin FJ, Spinelli D, Chiarini A. Stereoselective Behavior of the Functional Diltiazem Analogue 1-[(4-Chlorophenyl)sulfonyl]-2-(2-thienyl)pyrrolidine, a New L-Type Calcium Channel Blocker. J Med Chem 2009; 52:6637-48. [DOI: 10.1021/jm9008696] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Emanuele Carosati
- Dipartimento di Chimica, Università degli Studi di Perugia, Via Elce di Sotto 10, 06123 Perugia, Italy
| | - Roberta Budriesi
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Bologna, Via Belmeloro 6, 40126 Bologna, Italy
| | - Pierfranco Ioan
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Bologna, Via Belmeloro 6, 40126 Bologna, Italy
| | - Gabriele Cruciani
- Dipartimento di Chimica, Università degli Studi di Perugia, Via Elce di Sotto 10, 06123 Perugia, Italy
| | - Fabio Fusi
- Dipartimento di Neuroscienze, Università degli Studi di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Maria Frosini
- Dipartimento di Neuroscienze, Università degli Studi di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Simona Saponara
- Dipartimento di Neuroscienze, Università degli Studi di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Francesco Gasparrini
- Dipartimento di Chimica e Tecnologie del Farmaco, Università “La Sapienza”, Piazzale A. Moro 5, 00185 Roma, Italy
| | - Alessia Ciogli
- Dipartimento di Chimica e Tecnologie del Farmaco, Università “La Sapienza”, Piazzale A. Moro 5, 00185 Roma, Italy
| | - Claudio Villani
- Dipartimento di Chimica e Tecnologie del Farmaco, Università “La Sapienza”, Piazzale A. Moro 5, 00185 Roma, Italy
| | - Philip J. Stephens
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482
| | - Frank J. Devlin
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482
| | - Domenico Spinelli
- Dipartimento di Chimica “G. Ciamician”, Università degli Studi di Bologna, Via Selmi 2, 40126 Bologna, Italy
| | - Alberto Chiarini
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Bologna, Via Belmeloro 6, 40126 Bologna, Italy
| |
Collapse
|
25
|
Saponara S, Sgaragli G, Fusi F. Quercetin antagonism of Bay K 8644 effects on rat tail artery L-type Ca2+ channels. Eur J Pharmacol 2008; 598:75-80. [DOI: 10.1016/j.ejphar.2008.08.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2008] [Revised: 08/11/2008] [Accepted: 08/22/2008] [Indexed: 01/06/2023]
|
26
|
Medeiros MAA, Nunes XP, Barbosa-Filho JM, Lemos VS, Pinho JF, Roman-Campos D, de Medeiros IA, Araújo DAM, Cruz JS. (S)-reticuline induces vasorelaxation through the blockade of L-type Ca(2+) channels. Naunyn Schmiedebergs Arch Pharmacol 2008; 379:115-25. [PMID: 18825370 DOI: 10.1007/s00210-008-0352-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Accepted: 09/08/2008] [Indexed: 11/24/2022]
Abstract
In Brazil, various species of the genus Ocotea are used in folk medicine for treating several diseases. The chemical characterization of this plant showed the presence of alkaloids belonging to the benzyltetrahydroisoquinoline family, the major component of which is (S)-reticuline. The present study investigated whether (S)-reticuline exerts an inhibitory effect on smooth muscle L-type Ca(2+) channels. Tension measurements and patch clamp techniques were utilized to study the effects of (S)-reticuline. Whole-cell Ca(2+) currents were measured using the A7r5 smooth muscle cell line. (S)-reticuline antagonized CaCl(2)- and KCl-induced contractions and elicited vasorelaxation. It also reduced the voltage-activated peak amplitude of I (Ca,L) in a concentration-dependent manner. (S)-reticuline did not change the characteristics of current density vs. voltage relationship. (S)-reticuline shifted leftwards the steady-state inactivation curve of I (Ca,L). The application of dibutyryl cyclic adenosine monophosphate to the cell decreased the amplitude of Ca(2+) currents. In cells pretreated with forskolin, an adenylate cyclase activator, the addition of (S)-reticuline caused further inhibition of the Ca(2+) currents suggesting an additive effect. The results obtained show that (S)-reticuline elicits vasorelaxation probably due to the blockade of the L-type voltage-dependent Ca(2+) current in rat aorta. The reported effect may contribute to the potential cardioprotective efficacy of (S)-reticuline.
Collapse
Affiliation(s)
- Marcos Antônio A Medeiros
- Laboratory of Pharmaceutical Technology (LTF), Universidade Federal da Paraíba, João Pessoa, PB, Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Stockwin LH, Bumke MA, Yu SX, Webb SP, Collins JR, Hollingshead MG, Newton DL. Proteomic Analysis Identifies Oxidative Stress Induction by Adaphostin. Clin Cancer Res 2007; 13:3667-81. [PMID: 17575232 DOI: 10.1158/1078-0432.ccr-07-0025] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Activities distinct from inhibition of Bcr/abl have led to adaphostin (NSC 680410) being described as "a drug in search of a mechanism." In this study, proteomic analysis of adaphostin-treated myeloid leukemia cell lines was used to further elucidate a mechanism of action. EXPERIMENTAL DESIGN HL60 and K562 cells treated with adaphostin for 6, 12, or 24 h were analyzed using two-dimensional PAGE. Differentially expressed spots were excised, digested with trypsin, and analyzed by liquid chromatography-tandem mass spectrometry. The contribution of the redox-active hydroquinone group in adaphostin was also examined by carrying out proteomic analysis of HL60 cells treated with a simple hydroquinone (1,4-dihydroxybenzene) or H(2)O(2). RESULTS Analysis of adaphostin-treated cells identified 49 differentially expressed proteins, the majority being implicated in the response to oxidative stress (e.g., CALM, ERP29, GSTP1, PDIA1) or induction of apoptosis (e.g., LAMA, FLNA, TPR, GDIS). Interestingly, modulation of these proteins was almost fully prevented by inclusion of an antioxidant, N-acetylcysteine. Validation of the proteomic data confirmed GSTP1 as an adaphostin resistance gene. Subsequent analysis of HL60 cells treated with 1,4-dihydroxybenzene or H(2)O(2) showed similar increases in intracellular peroxides and an almost identical proteomic profiles to that of adaphostin treatment. Western blotting of a panel of cell lines identified Cu/Zn superoxide dismutase (SOD) as correlating with adaphostin resistance. The role of SOD as a second adaphostin resistance gene was confirmed by demonstrating that inhibition of SOD using diethyldithiocarbamate increased adaphostin sensitivity, whereas transfection of SOD I attenuated toxicity. Importantly, treatment with 1,4-dihydroxybenzene or H(2)O(2) replicated adaphostin-induced Bcr/abl polypeptide degradation, suggesting that kinase inhibition is a ROS-dependent phenomenon. CONCLUSION Adaphostin should be classified as a redox-active-substituted dihydroquinone.
Collapse
Affiliation(s)
- Luke H Stockwin
- Developmental Therapeutics Program, Science Applications International Corporation Frederick, Frederick, Maryland 21702, USA
| | | | | | | | | | | | | |
Collapse
|
28
|
Fusi F, Ferrara A, Sgaragli G, Saponara S. Mechanisms of the antispasmodic activity of 3,5-di-t-butyl catechol (DTCAT) on rat vascular smooth muscles. Eur J Pharmacol 2007; 561:112-20. [PMID: 17292353 DOI: 10.1016/j.ejphar.2006.12.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 12/20/2006] [Accepted: 12/21/2006] [Indexed: 11/15/2022]
Abstract
In skeletal muscle sarcoplasmic reticulum vesicles, 3,5-di-t-butyl catechol (DTCAT) promotes the release of Ca(2+) through the activation of ryanodine receptor Ca(2+) channels. DTCAT mechanical and electrophysiological effects have now been investigated in rat aorta rings and single tail artery myocytes. Rat aorta rings incubated with either 30 microM ryanodine or 100 microM DTCAT developed tension, which averaged 36% and 7%, respectively, of that induced by phenylephrine. DTCAT reduced concentration-dependently both aorta ring contractions to high K(+) (IC(50)=13.5 microM) and L-type Ba(2+) current (IC(50)=22.0 microM) in isolated myocytes. Tetraethylammonium did not reverse the antispasmodic effect of DTCAT in rings stimulated with either 25 or 60 mM K(+). DTCAT relaxed concentration-dependently phenylephrine-pre-contracted rings with intact endothelium (IC(50)=10.9 microM). This effect was markedly reduced by pre-incubation of rings with 100 microM Nomega-nitro-l-arginine methyl ester. DTCAT antagonised phenylephrine-induced contractions in endothelium-deprived rings, either in the presence or in the absence of ryanodine (IC(50)=18.7 microM and 39.8 microM, respectively). Furthermore, both DTCAT (IC(50)=53.3 microM) and ryanodine reduced significantly the response to phenylephrine in the absence of extracellular Ca(2+). Phenylephrine-stimulated influx of extracellular Ca(2+) was markedly inhibited when tissues were pre-treated with DTCAT (IC(50)=19.0 microM) as well as nifedipine. DTCAT (>100 microM) was also able to antagonise the contractions induced by phorbol 12-myristate, 13-acetate. In conclusion, this is the first demonstration that DTCAT inhibits vascular smooth muscle voltage-operated Ca(2+) channels and promotes the release of endothelial nitric oxide. Ryanodine receptor Ca(2+) channels activation or the impairment of the contractile apparatus by DTCAT seem to play a secondary role in its vascular activity.
Collapse
MESH Headings
- Animals
- Aorta/drug effects
- Aorta/metabolism
- Calcium/metabolism
- Calcium Channels/drug effects
- Calcium Channels/metabolism
- Catechols/pharmacology
- Dose-Response Relationship, Drug
- Electrophysiology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Male
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Nitric Oxide/metabolism
- Rats
- Rats, Sprague-Dawley
- Ryanodine/pharmacology
- Ryanodine Receptor Calcium Release Channel/drug effects
- Ryanodine Receptor Calcium Release Channel/metabolism
- Spasm/drug therapy
Collapse
Affiliation(s)
- Fabio Fusi
- Dipartimento di Scienze Biomediche, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy.
| | | | | | | |
Collapse
|
29
|
Fusi F, Ferrara A, Zalatnai A, Molnar J, Sgaragli G, Saponara S. Vascular activity of two silicon compounds, ALIS 409 and ALIS 421, novel multidrug-resistance reverting agents in cancer cells. Cancer Chemother Pharmacol 2007; 61:443-51. [PMID: 17464509 DOI: 10.1007/s00280-007-0488-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2006] [Accepted: 03/27/2007] [Indexed: 10/23/2022]
Abstract
PURPOSE The aim of this study was to investigate the effects of two novel multidrug-resistance reverting agents, ALIS 409 [1,3-dimethyl-1,3-p-fluorophenyl-1,3(3-morfolinopropyl)-1,3-disiloxan dihydrochloride] and ALIS 421 [1,3-dimethyl-1,3-(4-fluorophenyl)-1,3[3(4-buthyl)-(1-piperazinyl)-propyl]-1,3-disiloxan tetrahydrochloride], on vascular functions in vitro. EXPERIMENTAL DESIGN A comparison of their mechanical and electrophysiological actions in rat aorta rings and single rat tail artery myocytes, respectively, was performed. RESULTS In endothelium-denuded rat aorta rings, ALIS 409 and ALIS 421 antagonized 60 mM K(+)-induced contraction in a concentration-dependent manner with IC(50) values of 52.2 and 15.5 microM, respectively. ALIS 409 and ALIS 421 inhibited L-type Ca(2+) current recorded in artery myocytes in a concentration-dependent manner with IC(50) values of 6.4 and 5.6 microM, respectively. In rat aorta, ALIS 409 and ALIS 421 antagonized the sustained tonic contraction induced by phenylephrine with IC(50) values of 58.0 and 13.7 microM (endothelium-denuded rings) and of 73.9 and 31.9 microM (endothelium-intact rings), respectively. In endothelium-denuded rings, ryanodine reduced significantly the response to phenylephrine in the absence of extracellular Ca(2+) whereas nifedipine, ALIS 409 or ALIS 421 did not affect it. Phenylephrine-stimulated influx of extracellular Ca(2+) was markedly reduced when tissues were pretreated with ALIS 409, ALIS 421 or nifedipine, and stimulated when they were pretreated with ryanodine. Application of ALIS 409 (up to 100 microM) to intact rat aorta rings failed to induce mechanical responses. CONCLUSIONS Our results provide functional evidence that the myorelaxing effect elicited either by ALIS 409 or by ALIS 421 involved mainly the direct blockade of extracellular Ca(2+) influx. This effect, however, took place at concentrations much higher than those effective as modifiers of multidrug resistance in cancer cells.
Collapse
MESH Headings
- Adrenergic alpha-Agonists/pharmacology
- Animals
- Aorta, Thoracic/drug effects
- Calcium Channel Blockers/pharmacology
- Calcium Signaling/drug effects
- Drug Resistance, Multiple/drug effects
- Drug Resistance, Neoplasm/drug effects
- Genes, MDR/drug effects
- In Vitro Techniques
- Male
- Morpholines/pharmacology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Neoplasms/drug therapy
- Neoplasms/pathology
- Patch-Clamp Techniques
- Phenylephrine/pharmacology
- Piperazines/pharmacology
- Rats
- Rats, Sprague-Dawley
- Siloxanes/pharmacology
Collapse
Affiliation(s)
- Fabio Fusi
- Dipartimento di Scienze Biomediche, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy.
| | | | | | | | | | | |
Collapse
|
30
|
Khattab MM, Al-Hrasen MN. Contractile activity of ATP and diadenosine tetraphosphate on urinary bladder in the rats: role of superoxide anion and urothelium. ACTA ACUST UNITED AC 2006; 26:149-56. [PMID: 16553643 DOI: 10.1111/j.1474-8673.2006.00357.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Both ATP and diadenosine tetraphosphate (AP(4)A) produced a dose-dependent contraction of rat isolated urinary bladder rings. The AP(4)A dose-response curve was to the left of that of ATP, and the maximum response was greater than that produced by ATP. Mechanical removal of the urothelium increased the contractile response to ATP by between 53% and 71%, and that to AP(4)A by 42% (at highest AP(4)A concentration) to 68% at lower concentration. Inhibition of Cu/Zn superoxide dismutase with diethylthiocarbamate (DETCA, 5 mm) significantly reduced the ATP-evoked contraction by 31% (at high ATP concentration) to 40% at low ATP concentration. Similarly, the AP(4)A-induced contractions were significantly decreased by 27% at low AP(4)A level to 38% at higher concentrations. Induction of exogenous superoxide anion stress by the use of the superoxide anion generator, pyrogallol (0.5 mm), significantly decreased both ATP- and AP(4)A-induced contractions of the rat urinary bladder over the whole dose range. Contractile responses to ATP decreased by 36-40%, and those to AP(4)A by 44-49%. In conclusion, the urinary bladder urothelium exerts an inhibitory control over the purinergic contractility produced by adenine mononucleotides and dinucleotides. Superoxide anion stress, whether endogenous or exogenous, attenuates the ATP-induced as well as AP(4)A-induced contractility.
Collapse
Affiliation(s)
- M M Khattab
- Department of Pharmacology, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia
| | | |
Collapse
|
31
|
Camello-Almaraz C, Gomez-Pinilla PJ, Pozo MJ, Camello PJ. Mitochondrial reactive oxygen species and Ca2+ signaling. Am J Physiol Cell Physiol 2006; 291:C1082-8. [PMID: 16760264 DOI: 10.1152/ajpcell.00217.2006] [Citation(s) in RCA: 241] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitochondria are an important source of reactive oxygen species (ROS) formed as a side product of oxidative phosphorylation. The main sites of oxidant production are complex I and complex III, where electrons flowing from reduced substrates are occasionally transferred to oxygen to form superoxide anion and derived products. These highly reactive compounds have a well-known role in pathological states and in some cellular responses. However, although their link with Ca(2+) is well studied in cell death, it has been hardly investigated in normal cytosolic calcium concentration ([Ca(2+)](i)) signals. Several Ca(2+) transport systems are modulated by oxidation. Oxidation increases the activity of inositol 1,4,5-trisphosphate and ryanodine receptors, the main channels releasing Ca(2+) from intracellular stores in response to cellular stimulation. On the other hand, mitochondria are known to control [Ca(2+)](i) signals by Ca(2+) uptake and release during cytosolic calcium mobilization, specially in mitochondria situated close to Ca(2+) release channels. Mitochondrial inhibitors modify calcium signals in numerous cell types, including oscillations evoked by physiological stimulus. Although these inhibitors reduce mitochondrial Ca(2+) uptake, they also impair ROS production in several systems. In keeping with this effect, recent reports show that antioxidants or oxidant scavengers also inhibit physiological calcium signals. Furthermore, there is evidence that mitochondria generate ROS in response to cell stimulation, an effect suppressed by mitochondrial inhibitors that simultaneously block [Ca(2+)](i) signals. Together, the data reviewed here indicate that Ca(2+)-mobilizing stimulus generates mitochondrial ROS, which, in turn, facilitate [Ca(2+)](i) signals, a new aspect in the biology of mitochondria. Finally, the potential implications for biological modeling are discussed.
Collapse
|
32
|
Andreasen D, Friis UG, Uhrenholt TR, Jensen BL, Skøtt O, Hansen PB. Coexpression of Voltage-Dependent Calcium Channels Ca
v
1.2, 2.1a, and 2.1b in Vascular Myocytes. Hypertension 2006; 47:735-41. [PMID: 16505211 DOI: 10.1161/01.hyp.0000203160.80972.47] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Voltage-dependent Ca2+ channels Cav1.2 (L type) and Cav2.1 (P/Q type) are expressed in vascular smooth muscle cells (VSMCs) and are important for the contraction of renal resistance vessels. In the present study we examined whether native renal VSMCs coexpress L-, P-, and Q-type Ca2+ currents. The expression of both Cav2.1a (P-type) and Cav2.1b (Q-type) mRNA was demonstrated by RT-PCR in renal preglomerular vessels from rats and mice. Immunolabeling was performed on A7r5 cells, renal cryosections, and freshly isolated renal VSMCs with anti-Cav1.2 and anti-Cav2.1 antibodies. Conventional and confocal microscopy revealed expression of both channels in all of the smooth muscle cells. Whole-cell patch clamp on single preglomerular VSMCs from mice showed L-, P-, and Q-type currents. Blockade of the L-type currents by calciseptine (20 nmol/L) inhibited 35.6+/-3.9% of the voltage-dependent Ca2+ current, and blocking P-type currents (omega-agatoxin IVA 10 nmol/L) led to 20.2+/-3.0% inhibition, whereas 300 nmol/L of omega agatoxin IVA (blocking P/Q-type) inhibited 45.0+/-7.3%. In rat aortic smooth muscle cells (A7r5), blockade of L-type channels resulted in 28.5+/-6.1% inhibition, simultaneous blockade of L-type and P-type channels inhibited 58.0+/-11.8%, and simultaneous inhibition of L-, P-, and Q-type channels led to blockade (88.7+/-5.6%) of the Ca2+ current. We conclude that aortic and renal preglomerular smooth muscle cells express L-, P-, and Q-type voltage-dependent Ca2+ channels in the rat and mouse.
Collapse
MESH Headings
- Animals
- Aorta/cytology
- Aorta/metabolism
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/metabolism
- Calcium Channels, L-Type/physiology
- Calcium Channels, N-Type/genetics
- Calcium Channels, N-Type/metabolism
- Calcium Channels, N-Type/physiology
- Cell Line
- DNA, Recombinant
- Fluorescent Antibody Technique
- Genetic Variation
- Kidney/blood supply
- Male
- Mice
- Mice, Inbred C57BL
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/metabolism
- Patch-Clamp Techniques
- Protein Isoforms/genetics
- Protein Isoforms/metabolism
- Protein Isoforms/physiology
- Rats
- Rats, Sprague-Dawley
- Reverse Transcriptase Polymerase Chain Reaction
Collapse
Affiliation(s)
- Ditte Andreasen
- Physiology and Pharmacology, University of Southern Denmark, Odense, Denmark
| | | | | | | | | | | |
Collapse
|
33
|
Lee AK, Tse A. Dominant role of mitochondria in calcium homeostasis of single rat pituitary corticotropes. Endocrinology 2005; 146:4985-93. [PMID: 16081644 DOI: 10.1210/en.2005-0358] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The rise in cytosolic free Ca2+ concentration ([Ca2+]i) is the major trigger for secretion of ACTH from pituitary corticotropes. To better understand the shaping of the Ca2+ signal in corticotropes, we investigated the mechanisms regulating the depolarization-triggered Ca2+ signal using patch-clamp techniques and indo-1 fluorometry. The rate of cytosolic Ca2+ clearance was unaffected by inhibitors of Na+/Ca2+ exchanger or plasma membrane Ca2+-ATPase (PMCA), slightly slowed by sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) inhibitor, but dramatically slowed by mitochondrial uncouplers or inhibitor of mitochondrial uniporter. Measurements with rhod-2 revealed that depolarization-triggered increase in mitochondrial Ca2+ concentration. Thus, mitochondria have a dominant role in cytosolic Ca2+ clearance. Using the Mn2+ quench technique, we found the presence of a continuous basal Ca2+ influx in corticotropes. This basal Ca2+ influx was balanced by the combined actions of mitochondrial uniporter and PMCA and SERCA pumps. Inhibition of the mitochondrial uniporter or PMCA or SERCA pumps elevated basal [Ca2+]i. Using membrane capacitance measurement, we found that the change in the shape of the depolarization-triggered Ca2+ signal after mitochondrial inhibition was associated with enhancement of the exocytotic response. Thus, mitochondria have a dominant role in the regulation of Ca2+ signal and exocytosis in corticotropes.
Collapse
Affiliation(s)
- Andy K Lee
- 9-70 Medical Sciences Building, Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
| | | |
Collapse
|
34
|
Laporte R, Hui A, Laher I. Pharmacological modulation of sarcoplasmic reticulum function in smooth muscle. Pharmacol Rev 2005; 56:439-513. [PMID: 15602008 DOI: 10.1124/pr.56.4.1] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The sarco/endoplasmic reticulum (SR/ER) is the primary storage and release site of intracellular calcium (Ca2+) in many excitable cells. The SR is a tubular network, which in smooth muscle (SM) cells distributes close to cellular periphery (superficial SR) and in deeper aspects of the cell (deep SR). Recent attention has focused on the regulation of cell function by the superficial SR, which can act as a buffer and also as a regulator of membrane channels and transporters. Ca2+ is released from the SR via two types of ionic channels [ryanodine- and inositol 1,4,5-trisphosphate-gated], whereas accumulation from thecytoplasm occurs exclusively by an energy-dependent sarco-endoplasmic reticulum Ca2+-ATPase pump (SERCA). Within the SR, Ca2+ is bound to various storage proteins. Emerging evidence also suggests that the perinuclear portion of the SR may play an important role in nuclear transcription. In this review, we detail the pharmacology of agents that alter the functions of Ca2+ release channels and of SERCA. We describe their use and selectivity and indicate the concentrations used in investigating various SM preparations. Important aspects of cell regulation and excitation-contractile activity coupling in SM have been uncovered through the use of such activators and inhibitors of processes that determine SR function. Likewise, they were instrumental in the recent finding of an interaction of the SR with other cellular organelles such as mitochondria. Thus, an appreciation of the pharmacology and selectivity of agents that interfere with SR function in SM has greatly assisted in unveiling the multifaceted nature of the SR.
Collapse
Affiliation(s)
- Régent Laporte
- Ferring Research Institute, Inc., Ferring Pharmaceuticals, San Diego, California, USA
| | | | | |
Collapse
|
35
|
Fusi F, Sgaragli G, Saponara S. Mechanism of myricetin stimulation of vascular L-type Ca2+ current. J Pharmacol Exp Ther 2005; 313:790-7. [PMID: 15665142 DOI: 10.1124/jpet.104.080135] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
An in-depth analysis of the mechanism of the L-type Ca(2+) current [I(Ca(L))] stimulation induced by myricetin was performed in rat tail artery myocytes using the whole-cell patch-clamp method. Myricetin increased I(Ca(L)) in a frequency-, concentration-, and voltage-dependent manner. At holding potentials (V(h)) of -50 and -90 mV, the pEC(50) values were 4.9 +/- 0.1 and 4.2 +/- 0.1, respectively; the latter corresponded to the drug-apparent dissociation constant for resting channels, K(R), of 67.6 microM. Myricetin shifted the maximum of the current-voltage relationship by 10 mV in the hyperpolarizing direction but did not modify the threshold for I(Ca(L)) or the T-type Ca(2+) current. The Ca(2+) channel blockers nifedipine, verapamil, and diltiazem antagonized I(Ca(L)) in the presence of myricetin. Myricetin increased the time to peak of I(Ca(L)) in a voltage- and concentration-dependent manner. Washout reverted myricetin effect on both current kinetics and amplitude at V(h) of -90 mV while reverting only current kinetics at V(h) of -50 mV. At the latter V(h), myricetin shifted the voltage dependence of inactivation and activation curves to more negative potentials by 6.4 and 13.0 mV, respectively, in the mid-potential of the curves. At V(h) of -90 mV, myricetin shifted, in a concentration-dependent manner, the voltage dependence of the inactivation curve to more negative potentials with an apparent dissociation constant for inactivated channels (K(I)) of 13.8 muM. Myricetin induced a frequency- and V(h)-dependent block of I(Ca(L)). In conclusion, myricetin behaves as an L-type Ca(2+) channel agonist that stabilizes the channel in its inactivated state.
Collapse
Affiliation(s)
- Fabio Fusi
- Dipartimento di Scienze Biomediche, Università degli Studi di Siena, Italy.
| | | | | |
Collapse
|
36
|
O'Neill SC, Miller L, Hinch R, Eisner DA. Interplay between SERCA and sarcolemmal Ca2+ efflux pathways controls spontaneous release of Ca2+ from the sarcoplasmic reticulum in rat ventricular myocytes. J Physiol 2004; 559:121-8. [PMID: 15194743 PMCID: PMC1665077 DOI: 10.1113/jphysiol.2003.058917] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Waves of calcium-induced calcium release occur in a variety of cell types and have been implicated in the origin of cardiac arrhythmias. We have investigated the effects of inhibiting the SR Ca(2+)-ATPase (SERCA) with the reversible inhibitor 2',5'-di(tert-butyl)-1,4-benzohydroquinone (TBQ) on the properties of these waves. Cardiac myocytes were voltage clamped at a constant potential between -65 and -40 mV and spontaneous waves evoked by increasing external Ca(2+) concentration to 4 mm. Application of 100 microm TBQ decreased the frequency of waves. This was associated with increases of resting [Ca(2+)](i), the time constant of decay of [Ca(2+)](i) and the integral of the accompanying Na(+)-Ca(2+) exchange current. There was also a decrease in propagation velocity of the waves. There was an increase of the calculated Ca(2+) efflux per wave. The SR Ca(2+) content when a wave was about to propagate decreased to 91.7 +/- 3.2%. The period between waves increased in direct proportion to the Ca(2+) efflux per wave meaning that TBQ had no effect on the Ca(2+) efflux per unit time. We conclude that (i) decreased wave frequency is not a direct consequence of decreased Ca(2+) pumping by SERCA between waves but, rather, to more Ca(2+) loss on each wave; (ii) inhibiting SERCA increases the chance of spontaneous Ca(2+) release propagating at a given SR content.
Collapse
Affiliation(s)
- S C O'Neill
- Unit of Cardiac Physiology, 1.525 Stopford Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK. stephen.c.o'
| | | | | | | |
Collapse
|
37
|
Schlatterer C, Happle K, Lusche DF, Sonnemann J. Cytosolic [Ca2+] transients in dictyostelium discoideum depend on the filling state of internal stores and on an active sarco/endoplasmic reticulum calcium ATPase (SERCA) Ca2+ pump. J Biol Chem 2004; 279:18407-14. [PMID: 14973132 DOI: 10.1074/jbc.m307096200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Stimulation of Dictyostelium discoideum with cAMP evokes a change of the cytosolic free Ca(2+) concentration ([Ca(2+)](i)). We analyzed the role of the filling state of Ca(2+) stores for the [Ca(2+)] transient. Parameters tested were the height of the [Ca(2+)](i) elevation and the percentage of responding amoebae. After loading stores with Ca(2+), cAMP induced a [Ca(2+)](i) transient in many cells. Without prior loading, cAMP evoked a [Ca(2+)](i) change in a few cells only. This indicates that the [Ca(2+)](i) elevation is not mediated exclusively by Ca(2+) influx but also by Ca(2+) release from stores. Reducing the Ca(2+) content of the stores by EGTA preincubation led to a cAMP-activated [Ca(2+)](i) increase even at low extracellular [Ca(2+)]. Moreover, the addition of Ca(2+) itself elicited a capacitative [Ca(2+)](i) elevation. This effect was not observed when stores were emptied by the standard technique of inhibiting internal Ca(2+) pumps with 2,5-di-(t-butyl)-1,4-hydroquinone. Therefore, in Dictyostelium, an active internal Ca(2+)-ATPase is absolutely required to allow for Ca(2+) entry. No influence of the filling state of stores on Ca(2+) influx characteristics was found by the Mn(2+)-quenching technique, which monitors the rate of Ca(2+) entry. Both basal and cAMP-activated Mn(2+) influx rates were similar in control cells and cells with empty stores. By contrast, determination of extracellular free Ca(2+) concentration ([Ca(2+)](e)) changes, which represent the sum of Ca(2+) influx and efflux, revealed a higher rate of [Ca(2+)](e) decrease in EGTA-treated than in control amoebae. We conclude that emptying of Ca(2+) stores does not change the rate of Ca(2+) entry but results in inhibition of the plasma membrane Ca(2+)-ATPase. Furthermore, the activities of the Ca(2+) transport ATPases of the stores are of crucial importance for the regulation of [Ca(2+)](i) changes.
Collapse
|
38
|
Saponara S, Kawase M, Shah A, Motohashi N, Molnar J, Ugocsai K, Sgaragli G, Fusi F. 3,5-Dibenzoyl-4-(3-phenoxyphenyl)-1,4-dihydro-2,6-dimethylpyridine (DP7) as a new multidrug resistance reverting agent devoid of effects on vascular smooth muscle contractility. Br J Pharmacol 2004; 141:415-22. [PMID: 14718255 PMCID: PMC1574217 DOI: 10.1038/sj.bjp.0705635] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The aim of this study was to investigate the effects of 3,5-diacetyl- (DP1-DP5) and 3,5-dibenzoyl-1,4-dihydropyridines (DP6-DP11) on vascular functions in vitro, by comparing their mechanical and electrophysiological actions in rat aorta rings and single rat tail artery myocytes, respectively, and to quantify their multidrug resistance (MDR)-reversing activity in L5178 Y mouse T-lymphoma cells transfected with MDR1 gene. In rat aorta, the 11 compounds tested, but 3,5-dibenzoyl-4-(3-phenoxyphenyl)-1,4-dihydro-2,6-dimethylpyridine (DP7), 3,5-dibenzoyl-4-(3-chlorophenyl)-1,4-dihydro-2,6-dimethylpyridine (DP9), 3,5-dibenzoyl-4-(4-chlorophenyl)-1,4-dihydro-2,6-dimethylpyridine (DP10) and 3,5-dibenzoyl-4-phenyl-1,4-dihydro-2,6-dimethylpyridine (DP11), antagonized 60 mm K+ (K60)-induced contraction in a concentration-dependent manner, with IC50 (m) values ranging between 5.65 x 10(-7) and 2.23 x 10(-5). The 11 dihydropyridines tested, but DP7, inhibited L-type Ca2+ current recorded in artery myocytes in a concentration-dependent manner, with IC50 (M) values ranging between 1.12 x 10(-6) and 6.90 x 10(-5). The K+ -channel opener cromakalim inhibited the Ca2+ -induced contraction in K30 but not that evoked in K60. On the contrary, DP7 was ineffective in both experimental conditions. When the rings were preincubated with 1 mm Ni2+ plus 1 microm nifedipine, the response to phenylephrine was significantly reduced by 2,5-di-t-butyl-1,4-benzohydroquinone (BHQ), a well-known endoplasmic reticulum Ca2+ -ATPase inhibitor. DP7 had no effects on this model system. In L5178 MDR cell line, the 11 dihydropyridines tested, but 3,5-diacetyl-4-(2-nitrophenyl)-1,4-dihydro-2,6-dimethylpyridine (DP1), 3,5-diacetyl-4-(3-phenoxyphenyl)-1,4-dihydro-2,6-dimethylpyridine (DP2) and 3,5-diacetyl-4-(3-chlorophenyl)-1,4-dihydro-2,6-dimethylpyridine (DP4), exhibited an MDR-reversing activity, with IC50 values ranging between 3.02 x 10(-7) and 4.27 x 10(-5), DP7 being the most potent. In conclusion, DP7 may represent a lead compound for the development of potent dihydropyridine MDR chemosensitizers devoid of vascular effects. British Journal of Pharmacology (2004) 141, 415-422. doi:10.1038/sj.bjp.0705635
Collapse
MESH Headings
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/physiology
- Cell Line, Tumor
- Dihydropyridines/chemistry
- Dihydropyridines/pharmacology
- Dose-Response Relationship, Drug
- Drug Resistance, Multiple/drug effects
- Drug Resistance, Multiple/physiology
- Leukemia L5178
- Mice
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Rats
- Vasoconstriction/drug effects
- Vasoconstriction/physiology
Collapse
Affiliation(s)
- Simona Saponara
- Istituto di Scienze Farmacologiche, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy
| | - Masami Kawase
- Faculty of Pharmaceutical Sciences, Josai University, Saitama 350-0295, Japan
| | - Anamik Shah
- Department of Chemistry, Saurashtra University, Rajkot-360 005, India
| | | | - Joseph Molnar
- Faculty of Medicine, Institute of Microbiology, Albert Szent-Györgyi Medical University Dom ter 10, Szeged H-6720, Hungary
| | - Katalin Ugocsai
- Faculty of Medicine, Institute of Microbiology, Albert Szent-Györgyi Medical University Dom ter 10, Szeged H-6720, Hungary
| | - Giampietro Sgaragli
- Istituto di Scienze Farmacologiche, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy
- Author for correspondence:
| | - Fabio Fusi
- Istituto di Scienze Farmacologiche, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy
| |
Collapse
|
39
|
Abstract
Elevation of ambient lactate concentration has been shown to alter contractile reactivity of vascular smooth muscle. We tested the hypothesis that lactate affects the disposition of intracellular free Ca2+. Porcine carotid artery strips were incubated in normal medium and in medium containing 10 mM sodium lactate or 10 mM sodium pyruvate. The rate and magnitude of contraction in response to K+-depolarization was depressed in lactate when compared to control. This was associated with a decrease in the onset and magnitude of the normal increase in free [Ca2+]i, as reflected by fluorescence of fura-2. Pyruvate had no effect on these variables. Depression in [Ca2+]i could not be attributed to a selective effect of lactate on pHi, membrane potential, or to enhanced superoxide production. Deletion of Ca2+ from the incubation medium negated depression of contractile responsiveness produced by lactate when compared to control. Lactate had no effect on contraction induced by 100 microM norepinephrine, which releases intracellular stored Ca2+. Thus, lactate inhibits arterial smooth muscle contraction by inhibiting influx of Ca2+ across the sarcolemma.
Collapse
Affiliation(s)
- John T Barron
- Section of Cardiology, Department of Medicine, Rush Medical College, Rush-Presbyterian-St. Luke's Medical Center, 1653 West Congress Parkway, Chicago, IL 60612, USA.
| | | |
Collapse
|
40
|
Fusi F, Saponara S, Frosini M, Gorelli B, Sgaragli G. L-type Ca2+ channels activation and contraction elicited by myricetin on vascular smooth muscles. Naunyn Schmiedebergs Arch Pharmacol 2003; 368:470-8. [PMID: 14618297 DOI: 10.1007/s00210-003-0836-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2003] [Accepted: 09/23/2003] [Indexed: 10/26/2022]
Abstract
The effects of myricetin (3,3',4',5,5',7-hesahydroxyflavone), a natural flavonoid found in edible plants, were studied on vascular smooth muscle L-type Ca(2+) channels by comparing its mechanical, radioligand binding, and electrophysiological properties to those of the Ca(2+) channel agonist (S)-(-)-Bay K 8644. In rat aorta rings, both myricetin and (S)-(-)-Bay K 8644 induced contractile responses, which were dependent upon prior exposure to K(+). At 15 mM K(+) (K15) the pEC(50) values for myricetin and (S)-(-)-Bay K 8644 were 4.43+/-0.03 and 7.92+/-0.13, respectively. Furthermore, the maximum tension response to myricetin was not significantly different from that elicited by either (S)-(-)-Bay K 8644 or K60. The Ca(2+) channel blockers nifedipine, verapamil and diltiazem antagonised and fully reverted myricetin-, (S)-(-)-Bay K 8644- as well as K60-induced contractions. Both myricetin and (S)-(-)-Bay K 8644 potentiated rat aorta ring responses to K(+), shifting the K(+) concentration-response curve to the left. (S)-(-)-Bay K 8644, but not myricetin, inhibited in a concentration-dependent manner (+)-[(3)H]PN200-110 binding in porcine aortic membranes. Electrophysiological recordings from single rat tail artery myocytes, under amphotericin B-perforated as well as conventional methods, showed that both myricetin and (S)-(-)-Bay K 8644 increased L-type Ba(2+) current (I(Ba(L))) and shifted the maximum of the current-voltage relationship by 10 mV in the hyperpolarising direction, without, however, modifying the threshold potential. Furthermore, (S)-(-)-Bay K 8644 accelerated both activation and inactivation kinetics of I(Ba(L)) while myricetin slowed down the activation kinetics. Finally, both (S)-(-)-Bay K 8644 and myricetin slowed down deactivation kinetics of I(Ba(L)). These results suggest that myricetin induces vasoconstriction by activating L-type Ca(2+) channel with similar efficacy but a site of action different to that of (S)-(-)-Bay K 8644.
Collapse
MESH Headings
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/antagonists & inhibitors
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology
- Animals
- Aorta/drug effects
- Aorta/metabolism
- Arteries
- Calcium Channel Agonists/pharmacology
- Calcium Channel Blockers/pharmacology
- Calcium Channels, L-Type/drug effects
- Calcium Channels, L-Type/physiology
- Dose-Response Relationship, Drug
- Drug Interactions
- Electrophysiology
- Flavonoids/antagonists & inhibitors
- Flavonoids/pharmacology
- In Vitro Techniques
- Male
- Muscle Contraction/drug effects
- Muscle Contraction/physiology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/physiology
- Patch-Clamp Techniques
- Potassium/pharmacology
- Radioligand Assay
- Rats
- Rats, Wistar
- Swine
- Tail
Collapse
Affiliation(s)
- Fabio Fusi
- Dipartimento di Scienze Anatomiche e Biomediche, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy.
| | | | | | | | | |
Collapse
|
41
|
Chang JP, Wong CJH, Davis PJ, Soetaert B, Fedorow C, Sawisky G. Role of Ca2+ stores in dopamine- and PACAP-evoked growth hormone release in goldfish. Mol Cell Endocrinol 2003; 206:63-74. [PMID: 12943990 DOI: 10.1016/s0303-7207(03)00234-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Growth hormone (GH) secretion, evoked by either pituitary adenylate cyclase-activating polypeptide (PACAP) or dopamine (DA), is dependent on both voltage-sensitive calcium channels (VSCC) and cAMP signaling in goldfish. We further characterized the involvement of Ca2+ in evoked release by PACAP and DA, by examining the sensitivity of evoked GH release to perturbations of Ca2+ signaling. Both VSCC and calmodulin/calmodulin-dependent kinase are involved in PACAP signaling as had been shown for DA. In spite of this apparent dependence on VSCC, blockade of TMB-8 but not ryanodine-sensitive intracellular Ca2+ stores inhibited both PACAP- and DA-evoked GH release. Using sarcoplasmic/endoplasmic reticulum Ca-ATPases (SERCA) inhibitors, we found BHQ blocked, whereas thapsigargin (Tg) enhanced stimulated GH release, suggesting that Tg-sensitive SERCA may counteract these cAMP-mobilizing neuroendocrine regulators by sequestering [Ca2+]i. As GH secretion stimulated by two endogenous gonadotropin-releasing hormones is not affected by Tg, it appears that distinct multiple Ca2+ stores mediate the hormone releasing response to different neuroendocrine regulators.
Collapse
Affiliation(s)
- J P Chang
- Department of Biological Sciences, University of Alberta, CW 405, Biological Sciences Building, Edmonton, Alta, Canada T6G 2E9.
| | | | | | | | | | | |
Collapse
|
42
|
Friis UG, Jørgensen F, Andreasen D, Jensen BL, Skøtt O. Molecular and functional identification of cyclic AMP-sensitive BKCa potassium channels (ZERO variant) and L-type voltage-dependent calcium channels in single rat juxtaglomerular cells. Circ Res 2003; 93:213-20. [PMID: 12842920 DOI: 10.1161/01.res.0000085041.70276.3d] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study aimed at identifying the type and functional significance of potassium channels and voltage-dependent calcium channels (Ca(v)) in single rat JG cells using whole-cell patch clamp. Single JG cells displayed outward rectification at positive membrane potentials and limited net currents between -60 and -10 mV. Blockade of K+ channels with TEA inhibited 83% of the current at +105 mV. Inhibition of KV channels with 4-AP inhibited 21% of the current. Blockade of calcium-sensitive voltage-gated K+ channels (BKCa) with charybdotoxin or iberiotoxin inhibited 89% and 82% of the current, respectively. Double immunofluorescence confirmed the presence of BKCa and renin in the same cell. cAMP increased the outward current by 1.6-fold, and this was inhibited by 74% with iberiotoxin. Expression of the cAMP-sensitive splice variant (ZERO) of BKCa was confirmed in single-sampled JG cells by RT-PCR. The resting membrane potential of JG cells was -32 mV and activation of BKCa with cAMP hyperpolarized cells on average 16 mV, and inhibition with TEA depolarized cells by 17 mV. The cells displayed typical high-voltage activated calcium currents sensitive to the L-type Ca(v) blocker calciseptine. RT-PCR analysis and double-immunofluorescence labeling showed coexpression of renin and L-type Ca(v) 1.2. The cAMP-mediated increase in exocytosis (measured as membrane capacitance) was inhibited by depolarization to +10 mV, and this inhibitory effect was blocked with calciseptine, whereas K+-blockers had no effect. We conclude that JG cells express functional cAMP-sensitive BKCa channels (the ZERO splice variant) and voltage-dependent L-type Ca2+ channels.
Collapse
MESH Headings
- Alternative Splicing
- Animals
- Calcium/metabolism
- Calcium/pharmacology
- Calcium Channels, L-Type/biosynthesis
- Calcium Channels, L-Type/drug effects
- Calcium Channels, L-Type/metabolism
- Cell Membrane/metabolism
- Cell Membrane/physiology
- Cells, Cultured
- Cyclic AMP/metabolism
- Cyclic AMP/pharmacology
- Electric Capacitance
- Ion Channel Gating/drug effects
- Juxtaglomerular Apparatus/cytology
- Juxtaglomerular Apparatus/metabolism
- Large-Conductance Calcium-Activated Potassium Channels
- Male
- Patch-Clamp Techniques
- Potassium/metabolism
- Potassium Channel Blockers/pharmacology
- Potassium Channels, Calcium-Activated/biosynthesis
- Potassium Channels, Calcium-Activated/classification
- Potassium Channels, Calcium-Activated/drug effects
- Potassium Channels, Calcium-Activated/genetics
- Potassium Channels, Calcium-Activated/metabolism
- Rats
- Rats, Sprague-Dawley
- Renin/metabolism
- Sodium/metabolism
Collapse
Affiliation(s)
- Ulla G Friis
- Department of Physiology and Pharmacology, University of Southern Denmark, Denmark.
| | | | | | | | | |
Collapse
|
43
|
Donaldson K, Stone V, Borm PJA, Jimenez LA, Gilmour PS, Schins RPF, Knaapen AM, Rahman I, Faux SP, Brown DM, MacNee W. Oxidative stress and calcium signaling in the adverse effects of environmental particles (PM10). Free Radic Biol Med 2003; 34:1369-82. [PMID: 12757847 DOI: 10.1016/s0891-5849(03)00150-3] [Citation(s) in RCA: 269] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
This review focuses on the potential role that oxidative stress plays in the adverse effects of PM(10). The central hypothesis is that the ability of PM(10) to cause oxidative stress underlies the association between increased exposure to PM(10) and both exacerbations of lung disease and lung cancer. Pulmonary inflammation may also underlie the cardiovascular effects seen following increased PM(10), although the mechanisms of the cardiovascular effects of PM(10) are not well understood. PM(10) is a complex mix of various particle types and several of the components of PM(10) are likely to be involved in the induction of oxidative stress. The most likely of these are transition metals, ultrafine particle surfaces, and organic compounds. In support of this hypothesis, oxidative stress arising from PM(10) has been shown to activate a number of redox-responsive signaling pathways in lung target cells. These pathways are involved in expression of genes that play a role in responses relevant to inflammation and pathological change, including MAPKs, NF-kappaB, AP-1, and histone acetylation. Oxidative stress from particles is also likely to play an important role in the carcinogenic effects associated with PM(10) and hydroxyl radicals from PM(10) cause DNA damage in vitro.
Collapse
Affiliation(s)
- Ken Donaldson
- Colt/ELEGI Laboratories, Centre for Inflammation Research, The University of Edinburgh Medical School, Edinburgh EH8 9AG, Scotland, UK.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Fusi F, Saponara S, Sgaragli G, Cargnelli G, Bova S. Ca(2+) entry blocking and contractility promoting actions of norbormide in single rat caudal artery myocytes. Br J Pharmacol 2002; 137:323-8. [PMID: 12237251 PMCID: PMC1573499 DOI: 10.1038/sj.bjp.0704877] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2002] [Revised: 07/08/2002] [Accepted: 07/15/2002] [Indexed: 11/09/2022] Open
Abstract
1 Aim of the present study was to investigate the effects of norbormide, a selective vasoconstrictor agent of the rat peripheral vessels, on the whole-cell voltage-dependent L-type Ca(2+) current (I(Ca(L))) of freshly isolated smooth muscle cells from the rat caudal artery, using either the conventional or the amphotericin B-perforated whole-cell patch-clamp method. 2 Norbormide decreased L-type Ca(2+) current in a concentration- and voltage-dependent manner, without modifying the threshold and the maximum of the current-voltage relationship. Norbormide-induced I(Ca(L)) inhibition was reversible upon wash-out. 3 Norbormide both shifted the voltage dependence of the steady-state inactivation curve to more negative potentials by about 16 mV, without affecting the activation curve, and decreased the slope of inactivation. Norbormide, however, did not modify both the activation and the inactivation kinetics of the I(Ca(L)). 4 Norbormide decreased I(Ca(L)) progressively during repetitive step depolarizations, with inhibition depending on the stimulation frequency (use-dependent block) as well as on the holding potential. 5 Addition of 50 micro M norbormide caused the contraction of all freshly isolated cells and also of those impaled with the perforated method, but not of those impaled with the conventional method (i.e. dialysed). 6 In conclusion, these results prove norbormide to be a vascular L-type Ca(2+) channel inhibitor, which preferentially acts on the inactivated and/or open state of the channel. In rat caudal artery smooth muscle, however, this mechanism does not result in a vasodilating effect since it is overwhelmed by the mechanism underlying norbormide-induced vasoconstriction.
Collapse
Affiliation(s)
- Fabio Fusi
- Istituto di Scienze Farmacologiche, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy.
| | | | | | | | | |
Collapse
|
45
|
Saponara S, Sgaragli G, Fusi F. Quercetin as a novel activator of L-type Ca(2+) channels in rat tail artery smooth muscle cells. Br J Pharmacol 2002; 135:1819-27. [PMID: 11934824 PMCID: PMC1573296 DOI: 10.1038/sj.bjp.0704631] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. The aim of this study was to investigate the effects of quercetin, a natural polyphenolic flavonoid, on voltage-dependent Ca(2+) channels of smooth muscle cells freshly isolated from the rat tail artery, using either the conventional or the amphotericin B-perforated whole-cell patch-clamp method. 2. Quercetin increased L-type Ca(2+) current [I(Ca(L))] in a concentration- (pEC(50)=5.09+/-0.05) and voltage-dependent manner and shifted the maximum of the current-voltage relationship by 10 mV in the hyperpolarizing direction, without, however, modifying the threshold and the equilibrium potential for Ca(2+). 3. Quercetin-induced I(Ca(L)) stimulation was reversible upon wash-out. T-type Ca(2+) current was not affected by quercetin. Quercetin shifted the voltage dependence of the steady-state inactivation and activation curves to more negative potentials by about 5.5 and 7.5 mV respectively, in the mid-potential of the curves as well as increasing the slope of activation. Quercetin slowed both the activation and the deactivation kinetics of the I(Ca(L)). The inactivation time course was also slowed but only at voltages higher than 10 mV. Moreover quercetin slowed the rate of recovery from inactivation. 4. These results prove quercetin to be a naturally-occurring L-type Ca(2+) channel activator.
Collapse
MESH Headings
- Animals
- Calcium Channels, L-Type/metabolism
- Calcium Channels, L-Type/physiology
- Electrophysiology
- Kinetics
- Male
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiology
- Patch-Clamp Techniques
- Quercetin/pharmacology
- Rats
- Tail
Collapse
Affiliation(s)
- Simona Saponara
- Istituto di Scienze Farmacologiche, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy
| | - Giampietro Sgaragli
- Istituto di Scienze Farmacologiche, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy
- Author for correspondence:
| | - Fabio Fusi
- Istituto di Scienze Farmacologiche, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy
| |
Collapse
|