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Bkaily G, Jacques D. Morphological and Functional Remodeling of Vascular Endothelium in Cardiovascular Diseases. Int J Mol Sci 2023; 24:ijms24031998. [PMID: 36768314 PMCID: PMC9916505 DOI: 10.3390/ijms24031998] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/29/2022] [Accepted: 01/01/2023] [Indexed: 01/21/2023] Open
Abstract
The vascular endothelium plays a vital role during embryogenesis and aging and is a cell monolayer that lines the blood vessels. The immune system recognizes the endothelium as its own. Therefore, an abnormality of the endothelium exposes the tissues to the immune system and provokes inflammation and vascular diseases such as atherosclerosis. Its secretory role allows it to release vasoconstrictors and vasorelaxants as well as cardio-modulatory factors that maintain the proper functioning of the circulatory system. The sealing of the monolayer provided by adhesion molecules plays an important role in cardiovascular physiology and pathology.
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Secondo A, Petrozziello T, Tedeschi V, Boscia F, Pannaccione A, Molinaro P, Annunziato L. Nuclear localization of NCX: Role in Ca 2+ handling and pathophysiological implications. Cell Calcium 2019; 86:102143. [PMID: 31865040 DOI: 10.1016/j.ceca.2019.102143] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 12/10/2019] [Accepted: 12/10/2019] [Indexed: 02/05/2023]
Abstract
Numerous lines of evidence indicate that nuclear calcium concentration ([Ca2+]n) may be controlled independently from cytosolic events by a local machinery. In particular, the perinuclear space between the inner nuclear membrane (INM) and the outer nuclear membrane (ONM) of the nuclear envelope (NE) likely serves as an intracellular store for Ca2+ ions. Since ONM is contiguous with the endoplasmic reticulum (ER), the perinuclear space is adjacent to the lumen of ER thus allowing a direct exchange of ions and factors between the two organelles. Moreover, INM and ONM are fused at the nuclear pore complex (NPC), which provides the only direct passageway between the nucleoplasm and cytoplasm. However, due to the presence of ion channels, exchangers and transporters, it has been generally accepted that nuclear ion fluxes may occur across ONM and INM. Within the INM, the Na+/Ca2+ exchanger (NCX) isoform 1 seems to play an important role in handling Ca2+ through the different nuclear compartments. Particularly, nuclear NCX preferentially allows local Ca2+ flowing from nucleoplasm into NE lumen thanks to the Na+ gradient created by the juxtaposed Na+/K+-ATPase. Such transfer reduces abnormal elevation of [Ca2+]n within the nucleoplasm thus modulating specific transductional pathways and providing a protective mechanism against cell death. Despite very few studies on this issue, here we discuss those making major contribution to the field, also addressing the pathophysiological implication of nuclear NCX malfunction.
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Affiliation(s)
- Agnese Secondo
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Naples, Italy.
| | - Tiziana Petrozziello
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Naples, Italy
| | - Valentina Tedeschi
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Naples, Italy
| | - Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Naples, Italy
| | - Anna Pannaccione
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Naples, Italy
| | - Pasquale Molinaro
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Naples, Italy
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Zhu L, Lu Y, Zhang J, Hu Q. Subcellular Redox Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 967:385-398. [DOI: 10.1007/978-3-319-63245-2_25] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Bkaily G, Avedanian L, Al-Khoury J, Ahmarani L, Perreault C, Jacques D. Receptors and ionic transporters in nuclear membranes: new targets for therapeutical pharmacological interventions. Can J Physiol Pharmacol 2012; 90:953-65. [DOI: 10.1139/y2012-077] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Work from our group and other laboratories showed that the nucleus could be considered as a cell within a cell. This is based on growing evidence of the presence and role of nuclear membrane G-protein coupled receptors and ionic transporters in the nuclear membranes of many cell types, including vascular endothelial cells, endocardial endothelial cells, vascular smooth muscle cells, cardiomyocytes, and hepatocytes. The nuclear membrane receptors were found to modulate the functioning of ionic transporters at the nuclear level, and thus contribute to regulation of nuclear ionic homeostasis. Nuclear membranes of the mentioned types of cells possess the same ionic transporters; however, the type of receptors is cell-type dependent. Regulation of cytosolic and nuclear ionic homeostasis was found to be dependent upon a tight crosstalk between receptors and ionic transporters of the plasma membranes and those of the nuclear membrane. This crosstalk seems to be the basis for excitation–contraction coupling, excitation–secretion coupling, and excitation – gene expression coupling. Further advancement in this field will certainly shed light on the role of nuclear membrane receptors and transporters in health and disease. This will in turn enable the successful design of a new class of drugs that specifically target such highly vital nuclear receptors and ionic transporters.
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Affiliation(s)
- Ghassan Bkaily
- Department of Anatomy and Cell Biology, Faculty of Medicine, Université de Sherbrooke, 3001 12th Avenue North, Sherbrooke, QC J1H 5N4, Canada
| | - Levon Avedanian
- Department of Anatomy and Cell Biology, Faculty of Medicine, Université de Sherbrooke, 3001 12th Avenue North, Sherbrooke, QC J1H 5N4, Canada
| | - Johny Al-Khoury
- Department of Anatomy and Cell Biology, Faculty of Medicine, Université de Sherbrooke, 3001 12th Avenue North, Sherbrooke, QC J1H 5N4, Canada
| | - Lena Ahmarani
- Department of Anatomy and Cell Biology, Faculty of Medicine, Université de Sherbrooke, 3001 12th Avenue North, Sherbrooke, QC J1H 5N4, Canada
| | - Claudine Perreault
- Department of Anatomy and Cell Biology, Faculty of Medicine, Université de Sherbrooke, 3001 12th Avenue North, Sherbrooke, QC J1H 5N4, Canada
| | - Danielle Jacques
- Department of Anatomy and Cell Biology, Faculty of Medicine, Université de Sherbrooke, 3001 12th Avenue North, Sherbrooke, QC J1H 5N4, Canada
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Abrenica B, Pierce GN, Gilchrist JSC. Nucleoplasmic calcium regulation in rabbit aortic vascular smooth muscle cells. Can J Physiol Pharmacol 2003; 81:301-10. [PMID: 12733828 DOI: 10.1139/y03-005] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this study, we investigated whether nucleoplasmic free Ca2+ in aortic vascular smooth muscle cells (VSMCs) might be independently regulated from cytosolic free Ca2+. Understanding mechanisms and pathways responsible for this regulation is especially relevant given the role of a numerous intranuclear Ca2+-sensitive proteins in transcriptional regulation, apoptosis and cell division. The question of an independent regulatory mechanism remains largely unsettled because the previous use of intensitometric fluorophores (e.g., Fluo-3) has been criticized on technical grounds. To circumvent the potential problem of fluorescence artifact, we utilized confocal laser scanning microscopy to image intracellular Ca2+ movements with the ratiometric fluorophore Indo-1. In cultured rabbit VSMCs, we found sarcoplasmic reticulum (SR) Ca2+ ATPase (SERCA) pumps and ryanodine receptor (RyR) Ca2+ channel proteins to be discretely arranged within a perinuclear locus, as determined by fluorescent staining patterns of BODIPY FL thapsigargin and BODIPY FL-X Ry. When intracellular Ca2+ stores were mobilized by addition of thapsigargin (5 microM) and activatory concentrations of ryanodine (1 microM), Indo-1 ratiometric signals were largely restricted to the nucleoplasm. Cytosolic signals, by comparison, were relatively small and even then its spatial distribution was largely perinuclear rather homogeneous. These observations indicate perinuclear RyR and SERCA proteins are intimately involved in regulating VSMC nucleoplasmic Ca2+ concentrations. We also observed a similar pattern of largely nucleoplasmic Ca2+ mobilization upon exposure of cells to the immunosuppressant drug FK506 (tacrolimus), which binds to the RyR-associated immunophillin-binding proteins FKBP12 and FKBP12.6. However, initial FK506-induced nucleoplasmic Ca2+ mobilization was followed by marked reduction of Indo-1 signal intensity close to pretreatment levels. This suggested FK506 exerts both activatory and inhibitory effects upon RyR channels. The latter was reinforced by observed effects of FK506 to only reduce nucleoplasmic Indo-1 signal intensity when added following pretreatment with both activatory and inhibitory concentrations of ryanodine. These latter observations raise the possibility that VSMC nuclei represent an important sink of intracellular Ca2+ and may help explain vasodilatory actions of FK506 observed by others.
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Affiliation(s)
- Bernard Abrenica
- Department of Oral Biology, Division of Stroke and Vascular Disease, University of Manitoba, Winnipeg, MB R2H 2A6, Canada
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El-Bizri N, Bkaily G, Wang S, Jacques D, Regoli D, D'Orléans-Juste P, Sukarieh R. Bradykinin induced a positive chronotropic effect via stimulation of T- and L-type calcium currents in heart cells. Can J Physiol Pharmacol 2003; 81:247-58. [PMID: 12733823 DOI: 10.1139/y03-045] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Using Fluo-3 calcium dye confocal microscopy and spontaneously contracting embryonic chick heart cells, bradykinin (10(-10) M) was found to induce positive chronotropic effects by increasing the frequency of the transient increase of cytosolic and nuclear free Ca2+. Pretreatment of the cells with either B1 or B2 receptor antagonists (R126 and R817, respectively) completely prevented bradykinin (BK) induced positive chronotropic effects on spontaneously contracting single heart cells. Using the whole-cell voltage clamp technique and ionic substitution to separate the different ionic current species, our results showed that BK (10(-6) M) had no effect on fast Na+ inward current and delayed outward potassium current. However, both L- and T-type Ca2+ currents were found to be increased by BK in a dose-dependent manner (10(-10)-10(-7) M). The effects of BK on T- and L-type Ca2+ currents were partially blocked by the B1 receptor antagonist [Leu8]des-Arg9-BK (R592) (10(-7) M) and completely reversed by the B2 receptor antagonist D-Arg[Hyp3,D-Phe7,Leu8]BK (R-588) (10(-7) M) or pretreatment with pertussis toxin (PTX). These results demonstrate that BK induced a positive chronotropic effect via stimulation of T- and L-type Ca2+ currents in heart cells mainly via stimulation of B2 receptor coupled to PTX-sensitive G-proteins. The increase of both types of Ca2+ current by BK in heart cells may explain the positive inotropic and chronotropic effects of this hormone.
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MESH Headings
- Aniline Compounds
- Animals
- Bradykinin/pharmacology
- Bradykinin/physiology
- Bradykinin B1 Receptor Antagonists
- Bradykinin B2 Receptor Antagonists
- Calcium/metabolism
- Calcium Channel Blockers/pharmacology
- Calcium Channels, L-Type/drug effects
- Calcium Channels, L-Type/physiology
- Calcium Channels, T-Type/drug effects
- Calcium Channels, T-Type/physiology
- Cells, Cultured
- Chick Embryo
- Fluorescent Dyes
- In Vitro Techniques
- Microscopy, Confocal
- Myocytes, Cardiac/metabolism
- Nifedipine/pharmacology
- Patch-Clamp Techniques
- Potassium Channels/drug effects
- Potassium Channels/physiology
- Receptor, Bradykinin B1/physiology
- Receptor, Bradykinin B2/physiology
- Sodium Channels/drug effects
- Sodium Channels/physiology
- Stimulation, Chemical
- Time Factors
- Xanthenes
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Affiliation(s)
- Nesrine El-Bizri
- Department of Anatomy and Cell Biology, 3001 12th Avenue North, University of Sherbrooke, Sherbrooke, QC J1H 5N4 Canada
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Jacques D, Sader S, Perreault C, Fournier A, Pelletier G, Beck-Sickinger AG, Descorbeth M. Presence of neuropeptide Y and the Y1 receptor in the plasma membrane and nuclear envelope of human endocardial endothelial cells: modulation of intracellular calcium. Can J Physiol Pharmacol 2003; 81:288-300. [PMID: 12733827 DOI: 10.1139/y02-165] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aims of the present study were to investigate the presence and distribution of NPY and the Y1 receptor in endocardial endothelial cells (EECs), to verify if EECs can release NPY, and to determine if the effect of NPY on intracellular calcium is mediated via the Y1 receptor. Immunofluorescence, 3-D confocal microscopy and radioimmunoassay techniques were used on 20-week-old human fetal EECs. Our results showed that NPY and the Y1 receptor are present in human EECs (hEECs) and that their distributions are similar, the fluorescence labelling being higher in the nucleus and more particularly at the level of the nuclear envelope when compared with the cytosol. Using radioimmunoassay, we demonstrated that EECs are a source of NPY and can secrete this peptide upon a sustained increase of intracellular calcium ([Ca]i). Using fluo-3 and 3-D confocal microscopy technique, superfusion of hEECs as well as EECs isolated from rat adult hearts with increasing concentrations of NPY induced a dose-dependent, sustained increase in free cytosolic and nuclear Ca2+ levels. This effect of NPY on EEC [Ca]i was completely reversible upon washout of NPY and was partially blocked by BIBP3226, a selective Y1 receptor antagonist. The results suggest that NPY and Y1 receptors are present in the EECs of 20-week-old human fetal heart and they share the same distribution and localization inside the cell. In addition, EECs are able to secrete NPY in response to an increase in [Ca]i, and the Y1 receptor as well as other NPY receptors seem to participate in mediating the effects of NPY on [Ca]i in these cells. Thus, NPY released by EECs may modulate excitation-secretion coupling of these cells.
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Affiliation(s)
- Danielle Jacques
- Department of Anatomy and Cell Biology, Faculty of Medicine, University of Sherbrooke, Sherbrooke, QC J1H 5N4, Canada.
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Jacques D, Abdel Malak NA, Sader S, Perreault C. Angiotensin II and its receptors in human endocardial endothelial cells: role in modulating intracellular calcium. Can J Physiol Pharmacol 2003; 81:259-66. [PMID: 12733824 DOI: 10.1139/y03-046] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aims of the present study are to investigate the presence and distribution of angiotensin II (Ang II), as well as AT1 and AT2 receptors, in endocardial endothelial cells (EECs) and to determine if the effect of Ang II on intracellular calcium in these cells is mediated via the AT1 or the AT2 receptor. Immunofluorescence and 3D confocal microscopy techniques were used on 20-week-old fetal human EECs. Our results showed that Ang II and its receptors, the AT1 and the AT2 types, are present and exhibit a different distribution in human EECs. Ang II labelling is found throughout the cell with a fluorescence signal higher in the cytosol when compared with the nucleus. Like Ang II, the AT1 receptor fluorescence signal is also homogeneously distributed in human EECs but with a preferential labelling at the level of the nucleus, while the AT2 receptor labelling is solely present in the nucleus. Using fluo-3 and 3D confocal microscopy technique, superfusion of human EECs with increasing concentration of Ang II induced a dose-dependent sustained increase in free cytosolic and nuclear Ca2+ levels. This effect of Ang II on human EEC's intracellular Ca2+ ([Ca2+]) was completely prevented by losartan, an AT1 receptor antagonist. Our results suggest that Ang II, as well as AT1 and AT2 receptors, is present but differentially distributed in EECs of 20-week-old fetal human hearts, and that the AT1 receptor mediates the effects of Ang II on [Ca2+]i in these cells.
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MESH Headings
- Angiotensin II/metabolism
- Aniline Compounds
- Calcium/metabolism
- Cell Nucleus/metabolism
- Cells, Cultured
- Coronary Vessels/metabolism
- Cytosol/metabolism
- Endocardium/cytology
- Endocardium/metabolism
- Endothelium, Vascular/cytology
- Endothelium, Vascular/metabolism
- Fetus
- Fluorescent Antibody Technique
- Humans
- Microscopy, Confocal
- Receptor, Angiotensin, Type 1/metabolism
- Receptor, Angiotensin, Type 1/physiology
- Receptor, Angiotensin, Type 2/metabolism
- Receptor, Angiotensin, Type 2/physiology
- Receptors, Angiotensin/metabolism
- Receptors, Angiotensin/physiology
- Xanthenes
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Affiliation(s)
- Danielle Jacques
- Department of Anatomy and Cell Biology, Faculty of Medicine, University of Sherbrooke, Sherbrooke, QC J1H 5N4, Canada.
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Fellner SK, Arendshorst WJ. Ryanodine receptor and capacitative Ca2+ entry in fresh preglomerular vascular smooth muscle cells. Kidney Int 2000; 58:1686-94. [PMID: 11012902 DOI: 10.1046/j.1523-1755.2000.00329.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND A multiplicity of hormonal, neural, and paracrine factors regulates preglomerular arterial tone by stimulating calcium entry or mobilization. We have previously provided evidence for capacitative (store-operated) Ca2+ entry in fresh renal vascular smooth muscle cells (VSMCs). Ryanodine-sensitive receptors (RyRs) have recently been identified in a variety of nonrenal vascular beds. METHODS We isolated fresh rat preglomerular VSMCs with a magnetized microsphere/sieving technique; cytosolic Ca2+ ([Ca2+]i) was measured with fura-2 ratiometric fluorescence. RESULTS Ryanodine (3 micromol/L) increased [Ca2+]i from 79 to 138 nmol/L (P = 0.01). Nifedipine (Nif), given before or after ryanodine, was without effect. The addition of calcium (1 mmol/L) to VSMCs in calcium-free buffer did not alter resting [Ca2+]i. In Ca-free buffer containing Nif, [Ca2+]i rose from 61 to 88 nmol/L after the addition of the Ca2+-ATPase inhibitor cyclopiazonic acid and to 159 nmol/L after the addition of Ca2+ (1 mmol/L). Mn2+ quenched the Ca/fura signal, confirming divalent cation entry. In Ca-free buffer with Nif, [Ca2+]i increased from 80 to 94 nmol/L with the addition of ryanodine and further to 166 nmol/L after the addition of Ca2+ (1 mmol/L). Mn2+ quenching was again shown. Thus, emptying of the sarcoplasmic reticulum (SR) with ryanodine stimulated capacitative Ca2+ entry. CONCLUSION Preglomerular VSMCs have functional RyR, and a capacitative (store-operated) entry mechanism is activated by the depletion of SR Ca2+ with ryanodine, as is the case with inhibitors of SR Ca2+-ATPase.
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Affiliation(s)
- S K Fellner
- Department of Cell and Molecular Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7545, USA.
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Raicu M, Florea S, Costache G, Popov D, Simionescu M. Clotrimazole inhibits smooth muscle cell proliferation and has a vasodilator effect on resistance arteries. Fundam Clin Pharmacol 2000; 14:477-85. [PMID: 11129088 DOI: 10.1111/j.1472-8206.2000.tb00430.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Clotrimazole (CLT) is a drug known to interfere with cellular calcium homeostasis, which in turn is reported to intervene in cell proliferation and in the reactivity of small blood vessels. Experiments were designed to test the influence of CLT on the proliferative and vasorelaxant effect of bradykinin (BK) and on calcium homeostasis in smooth muscle cells (SMC). To this purpose two model systems were employed: (i) cultured human smooth muscle cells (HSMC), and (ii) isolated resistance arteries maintained in an organ bath. The effect of various concentrations of CLT (2-15 microM) on BK-induced proliferation of HSMC was quantitated by spectrometry following [3H]-thymidine incorporation, and intracellular calcium [Ca+]i was determined by spectrofluorimetry using Fura 2-AM assay. In other experiments the roles of BK receptor (AB2) and of thapsigargin were assessed. The reactivity of the resistance arteries was measured by the myograph technique, and the effects of BK, CLT, and NO synthase blocker, L-NAME were evaluated. The results showed that 10 microM CLT: (i) inhibits the BK-induced proliferation of HSMC by 45-50%: (ii) prevents the rise of [Ca2+]i induced by BK (120.8 +/- 12.4 nM vs. 235.8 +/- 34.1 nM), an cffect similar to that of "classic" L-type calcium channels blockers: (iii) reduces the release of Ca2+ entry induced by thapsigargin suggesting a possible inhibition of the capacitative Ca2+ entry. Organ bath assays showed that CLT enhanced the BK-induced relaxation of the resistance arteries by an endothelium NO-independent pathway. Together, these data suggest that the mechanism of action of CLT on SMC implies mainly a modification of intracellular calcium homeostasis, with a minor contribution of BK B2 receptors. These new distinctive features of CLT effects suggest the potential use of this drug in the therapy of cardiovascular diseases associated with SMC increased proliferation and impeded relaxation in small arteries, such as atherosclerosis and restenosis.
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Affiliation(s)
- M Raicu
- Institute of Cellular Biology and Pathology N. Simionescu, Bucharest, Romania.
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Jacques D, Sader S, El-Bizri N, Chouffani S, Hassan G, Shbaklo H. Neuropeptide Y induced increase of cytosolic and nuclear Ca2+ in heart and vascular smooth muscle cells. Can J Physiol Pharmacol 2000. [DOI: 10.1139/y99-127] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It was reported that neuropeptide Y (NPY) affects cardiac and vascular smooth muscle (VSM) function probably by increasing intracellular Ca2+. In this study, using fura-2 microfluorometry and fluo-3 confocal microscopy techniques for intracellular Ca2+ measurement, we attempted to verify whether the action of NPY receptor's stimulation in heart and VSM cells modulates intracellular Ca2+ and whether this effect is mediated via the Y1 receptor type. Using spontaneously contracting single ventricular heart cells of 10-day-old embryonic chicks and the fluo-3 confocal microscopy Ca2+ measurement technique to localize cytosolic ([Ca]c) and nuclear ([Ca]n) free Ca2+ level and distribution, 10-10 M of human (h) NPY significantly (P < 0.05) increased the frequency of cytosolic and nuclear Ca2+ transients during spontaneous contraction. Increasing the concentration of hNPY (10-9 M) did not further increase the frequency of Ca2+ transients. The L-type Ca2+ channel blocker, nifedipine (10-5 M), significantly (P < 0.001) blocked the spontaneous rise of intracellular Ca2+ in the absence and presence of hNPY (10-10 and 10-9 M). However, the selective Y1 receptor antagonist, BIBP3226 (10-6 M), significantly decreased the hNPY-induced (10-10 and 10-9 M) increase in the frequency of Ca2+ transients back to near the control level (P < 0.05). In resting nonworking heart and human aortic VSM cells, hNPY induced a dose-dependent sustained increase of basal resting intracellular Ca2+ with an EC50 near 10-9 M. This sustained increase was cytosolic and nuclear and was completely blocked by the Ca2+ chelator EGTA, and was significantly decreased by the Y1 receptor antagonist BIBP3226 in both heart (P < 0.05) and VSM (P < 0.01) cells. These results strongly suggest that NPY stimulates the resting basal steady-state Ca2+ influx through the sarcolemma and induces sustained increases of cytosolic and nuclear calcium, in good part, via the activation of the sarcolemma membrane Y1 receptor type in both resting heart and VSM cells. In addition, NPY also increased the frequency of Ca2+ transients during spontaneous contraction of heart cells mainly via the activation of the Y1 receptor type, which may explain in part the active cardiovascular action of this peptide.Key words: heart, vascular smooth muscle, neuropeptide Y, BIBP3226, calcium, nucleus.
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Kuwahara M, Miyaji T, Tsubone H. Angiotensin II type 1 receptor-mediated increase in cytosolic Ca(2+) and proliferation in mesothelial cells. Eur J Pharmacol 2000; 388:21-7. [PMID: 10657543 DOI: 10.1016/s0014-2999(99)00861-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We investigated the Ca(2+) signaling pathways of the response to angiotensin II in pleural mesothelial cells and the role of these Ca(2+) signaling pathways in mesothelial cell proliferation. Rat pleural mesothelial cells were maintained in vitro, and the Ca(2+) movement to angiotensin II was evaluated using the fluorescent Ca(2+) indicator fura 2. Furthermore, proliferation of mesothelial cells was assessed using a spectrophotometric 3-(4, 5-dimethylthazol-2-yl)-2,5-diphenyl-2H-tetrasodium bromide (MTT) assay. Angiotensin II (1 pM-100 microM) induced in mesothelial cells a biphasic elevation of intracellular Ca(2+) concentration ([Ca(2+)](i)) that consisted of a transient initial component, followed by a sustained component. Neither removal of extracellular Ca(2+) nor inhibition of Ca(2+) influx by 1 microM nifedipine affected the angiotensin II-induced initial transient elevation of [Ca(2+)](i) in mesothelial cells. Nifedipine did not block angiotensin II-induced sustained elevation of [Ca(2+)](i). Angiotensin II (1 pM-100 microM) had a proliferative effect on mesothelial cells in a dose-dependent manner. Angiotensin II type 1 (AT(1)) receptor antagonist ([Sar(1), Ile(8)]angiotensin II) inhibited both angiotensin II-induced elevation of [Ca(2+)](i) and proliferation of mesothelial cells. Pertussis toxin did not affect angiotensin II-induced responses. These results suggest that angiotensin II-induced responses to mesothelial cells are extremely dependent on the angiotensin AT(1) receptor coupled with pertussis toxin-insensitive G protein.
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Affiliation(s)
- M Kuwahara
- Department of Comparative Pathophysiology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan.
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Parkinson N, Bolsover S, Mason W. Nuclear and cytosolic calcium changes in osteoclasts stimulated with ATP and integrin-binding peptide. Cell Calcium 1998; 24:213-21. [PMID: 9883275 DOI: 10.1016/s0143-4160(98)90130-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Cytosolic calcium modulates the activity of osteoclasts, large multinucleate cells that resorb bone. Nuclear events, such as gene transcription, are also calcium-regulated in these cells, and fluorescence imaging has suggested that calcium signals produced by some stimuli are specifically targeted to, or amplified within, osteoclast nuclei. We used two alternative techniques of dye loading to examine the changes of intracellular calcium induced in rat osteoclasts by three stimuli. Osteoclasts loaded with the calcium indicator Fura-2 by the acetoxymethyl (AM) ester technique appeared to display marked nuclear calcium amplification. During stimulation with integrin-binding peptides, ATP, or high extracellular calcium, fluorescence ratios recorded from the nuclei rose higher than did ratios recorded from extranuclear regions. In contrast, nuclear calcium amplification was not observed after AM loading in the presence of the anion transport inhibitor sulfinpyrazone, nor in osteoclasts injected with Fura-2 conjugated to a high MW dextran. In these cells, nuclear fluorescence ratios were equal to the extranuclear values at all times: upon stimulation by an agonist, the nuclear and cytosolic calcium concentrations increased by the same amount. The calcium changes seen in stimulated osteoclasts can no longer be taken as evidence for the general validity of the phenomenon of nuclear calcium amplification.
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Affiliation(s)
- N Parkinson
- Department of Physiology, University College London, UK.
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