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Gomez HM, Haw TJ, Ilic D, Robinson P, Donovan C, Croft AJ, Vanka KS, Small E, Carroll OR, Kim RY, Mayall JR, Beyene T, Palanisami T, Ngo DTM, Zosky GR, Holliday EG, Jensen ME, McDonald VM, Murphy VE, Gibson PG, Horvat JC. Landscape fire smoke airway exposure impairs respiratory and cardiac function and worsens experimental asthma. J Allergy Clin Immunol 2024; 154:209-221.e6. [PMID: 38513838 DOI: 10.1016/j.jaci.2024.02.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 02/13/2024] [Accepted: 02/22/2024] [Indexed: 03/23/2024]
Abstract
BACKGROUND Millions of people are exposed to landscape fire smoke (LFS) globally, and inhalation of LFS particulate matter (PM) is associated with poor respiratory and cardiovascular outcomes. However, how LFS affects respiratory and cardiovascular function is less well understood. OBJECTIVE We aimed to characterize the pathophysiologic effects of representative LFS airway exposure on respiratory and cardiac function and on asthma outcomes. METHODS LFS was generated using a customized combustion chamber. In 8-week-old female BALB/c mice, low (25 μg/m3, 24-hour equivalent) or moderate (100 μg/m3, 24-hour equivalent) concentrations of LFS PM (10 μm and below [PM10]) were administered daily for 3 (short-term) and 14 (long-term) days in the presence and absence of experimental asthma. Lung inflammation, gene expression, structural changes, and lung function were assessed. In 8-week-old male C57BL/6 mice, low concentrations of LFS PM10 were administered for 3 days. Cardiac function and gene expression were assessed. RESULTS Short- and long-term LFS PM10 airway exposure increased airway hyperresponsiveness and induced steroid insensitivity in experimental asthma, independent of significant changes in airway inflammation. Long-term LFS PM10 airway exposure also decreased gas diffusion. Short-term LFS PM10 airway exposure decreased cardiac function and expression of gene changes relating to oxidative stress and cardiovascular pathologies. CONCLUSIONS We characterized significant detrimental effects of physiologically relevant concentrations and durations of LFS PM10 airway exposure on lung and heart function. Our study provides a platform for assessment of mechanisms that underpin LFS PM10 airway exposure on respiratory and cardiovascular disease outcomes.
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Affiliation(s)
- Henry M Gomez
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Immune Health Program, Hunter Medical Research Institute, Newcastle, Australia
| | - Tatt J Haw
- Heart and Stroke Research Program, Hunter Medical Research Institute, New Lambton Heights, Newcastle, Australia; College of Health, Medicine, and Wellbeing, Centre of Excellence Newcastle Cardio-Oncology Research Group, University of Newcastle, Callaghan, Newcastle, Australia
| | - Dusan Ilic
- Newcastle Institute for Energy and Resources, University of Newcastle, Callaghan, Australia
| | - Peter Robinson
- Newcastle Institute for Energy and Resources, University of Newcastle, Callaghan, Australia
| | - Chantal Donovan
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Immune Health Program, Hunter Medical Research Institute, Newcastle, Australia; School of Life Sciences, University of Technology Sydney, Faculty of Science, Sydney, Australia
| | - Amanda J Croft
- Heart and Stroke Research Program, Hunter Medical Research Institute, New Lambton Heights, Newcastle, Australia; College of Health, Medicine, and Wellbeing, Centre of Excellence Newcastle Cardio-Oncology Research Group, University of Newcastle, Callaghan, Newcastle, Australia
| | - Kanth S Vanka
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Immune Health Program, Hunter Medical Research Institute, Newcastle, Australia; Newcastle Institute for Energy and Resources, University of Newcastle, Callaghan, Australia
| | - Ellen Small
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Immune Health Program, Hunter Medical Research Institute, Newcastle, Australia
| | - Olivia R Carroll
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Immune Health Program, Hunter Medical Research Institute, Newcastle, Australia
| | - Richard Y Kim
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Immune Health Program, Hunter Medical Research Institute, Newcastle, Australia; School of Life Sciences, University of Technology Sydney, Faculty of Science, Sydney, Australia
| | - Jemma R Mayall
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Immune Health Program, Hunter Medical Research Institute, Newcastle, Australia
| | - Tesfalidet Beyene
- School of Medicine and Public Health, University of Newcastle and Asthma and Breathing Program, Hunter Medical Research Institute, Newcastle, Australia
| | - Thava Palanisami
- Global Innovative Centre for Advanced Nanomaterials, University of Newcastle, Callaghan, Australia
| | - Doan T M Ngo
- Heart and Stroke Research Program, Hunter Medical Research Institute, New Lambton Heights, Newcastle, Australia; College of Health, Medicine, and Wellbeing, Centre of Excellence Newcastle Cardio-Oncology Research Group, University of Newcastle, Callaghan, Newcastle, Australia
| | - Graeme R Zosky
- Menzies Institute for Medical Research, College of Health and Medicine, University of Tasmania, Hobart, Australia; College of Health and Medicine, Tasmanian School of Medicine, University of Tasmania, Hobart, Australia
| | - Elizabeth G Holliday
- School of Medicine and Public Health, University of Newcastle, Callaghan, Australia
| | - Megan E Jensen
- School of Medicine and Public Health, University of Newcastle and Asthma and Breathing Program, Hunter Medical Research Institute, Newcastle, Australia
| | - Vanessa M McDonald
- School of Medicine and Public Health, University of Newcastle and Asthma and Breathing Program, Hunter Medical Research Institute, Newcastle, Australia
| | - Vanessa E Murphy
- School of Medicine and Public Health, University of Newcastle and Asthma and Breathing Program, Hunter Medical Research Institute, Newcastle, Australia
| | - Peter G Gibson
- School of Medicine and Public Health, University of Newcastle and Asthma and Breathing Program, Hunter Medical Research Institute, Newcastle, Australia
| | - Jay C Horvat
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Immune Health Program, Hunter Medical Research Institute, Newcastle, Australia.
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Yao Y, Borkar NA, Zheng M, Wang S, Pabelick CM, Vogel ER, Prakash YS. Interactions between calcium regulatory pathways and mechanosensitive channels in airways. Expert Rev Respir Med 2023; 17:903-917. [PMID: 37905552 PMCID: PMC10872943 DOI: 10.1080/17476348.2023.2276732] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 10/25/2023] [Indexed: 11/02/2023]
Abstract
INTRODUCTION Asthma is a chronic lung disease influenced by environmental and inflammatory triggers and involving complex signaling pathways across resident airway cells such as epithelium, airway smooth muscle, fibroblasts, and immune cells. While our understanding of asthma pathophysiology is continually progressing, there is a growing realization that cellular microdomains play critical roles in mediating signaling relevant to asthma in the context of contractility and remodeling. Mechanosensitive pathways are increasingly recognized as important to microdomain signaling, with Piezo and transient receptor protein (TRP) channels at the plasma membrane considered important for converting mechanical stimuli into cellular behavior. Given their ion channel properties, particularly Ca2+ conduction, a question becomes whether and how mechanosensitive channels contribute to Ca2+ microdomains in airway cells relevant to asthma. AREAS COVERED Mechanosensitive TRP and Piezo channels regulate key Ca2+ regulatory proteins such as store operated calcium entry (SOCE) involving STIM and Orai channels, and sarcoendoplasmic (SR) mechanisms such as IP3 receptor channels (IP3Rs), and SR Ca2+ ATPase (SERCA) that are important in asthma pathophysiology including airway hyperreactivity and remodeling. EXPERT OPINION Physical and/or functional interactions between Ca2+ regulatory proteins and mechanosensitive channels such as TRP and Piezo can toward understanding asthma pathophysiology and identifying novel therapeutic approaches.
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Affiliation(s)
- Yang Yao
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Xi’an Medical University, Xi’an, Shaanxi, China
- Department of Anesthesiology, Mayo Clinic, Rochester, MN, USA
| | - Niyati A Borkar
- Department of Anesthesiology, Mayo Clinic, Rochester, MN, USA
| | - Mengning Zheng
- Department of Anesthesiology, Mayo Clinic, Rochester, MN, USA
- Department of Respiratory and Critical Care Medicine, Guizhou Province People’s Hospital, Guiyang, Guizhou, China
| | - Shengyu Wang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Xi’an Medical University, Xi’an, Shaanxi, China
| | - Christina M Pabelick
- Department of Anesthesiology, Mayo Clinic, Rochester, MN, USA
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Elizabeth R Vogel
- Department of Anesthesiology, Mayo Clinic, Rochester, MN, USA
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - YS Prakash
- Department of Anesthesiology, Mayo Clinic, Rochester, MN, USA
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
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Han YS, Delmotte P, Sieck GC. Effects of TNFα on Dynamic Cytosolic Ca 2 + and Force Responses to Muscarinic Stimulation in Airway Smooth Muscle. Front Physiol 2021; 12:730333. [PMID: 34393833 PMCID: PMC8363307 DOI: 10.3389/fphys.2021.730333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 07/09/2021] [Indexed: 11/30/2022] Open
Abstract
Previously, we reported that in airway smooth muscle (ASM), the cytosolic Ca2+ ([Ca2+]cyt) and force response induced by acetyl choline (ACh) are increased by exposure to the pro-inflammatory cytokine tumor necrosis factor α (TNFα). The increase in ASM force induced by TNFα was not associated with an increase in regulatory myosin light chain (rMLC20) phosphorylation but was associated with an increase in contractile protein (actin and myosin) concentration and an enhancement of Ca2+ dependent actin polymerization. The sensitivity of ASM force generation to elevated [Ca2+]cyt (Ca2+ sensitivity) is dynamic involving both the shorter-term canonical calmodulin-myosin light chain kinase (MLCK) signaling cascade that regulates rMLC20 phosphorylation and cross-bridge recruitment as well as the longer-term regulation of actin polymerization that regulates contractile unit recruitment and actin tethering to the cortical cytoskeleton. In this study, we simultaneously measured [Ca2+]cyt and force responses to ACh and explored the impact of 24-h TNFα on the dynamic relationship between [Ca2+]cyt and force responses. The temporal delay between the onset of [Ca2+]cyt and force responses was not affected by TNFα. Similarly, the rates of rise of [Ca2+]cyt and force responses were not affected by TNFα. The absence of an impact of TNFα on the short delay relationships between [Ca2+]cyt and force was consistent with the absence of an effect of [Ca2+]cyt and force on rMLC20 phosphorylation. However, the integral of the phase-loop plot of [Ca2+]cyt and force increased with TNFα, consistent with an impact on actin polymerization and, contractile unit recruitment and actin tethering to the cortical cytoskeleton.
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Affiliation(s)
- Young-Soo Han
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
| | - Philippe Delmotte
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
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Glück C, Ferrari KD, Binini N, Keller A, Saab AS, Stobart JL, Weber B. Distinct signatures of calcium activity in brain mural cells. eLife 2021; 10:e70591. [PMID: 34227466 PMCID: PMC8294852 DOI: 10.7554/elife.70591] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/15/2021] [Indexed: 12/15/2022] Open
Abstract
Pericytes have been implicated in various neuropathologies, yet little is known about their function and signaling pathways in health. Here, we characterized calcium dynamics of cortical mural cells in anesthetized or awake Pdgfrb-CreERT2;Rosa26< LSL-GCaMP6s > mice and in acute brain slices. Smooth muscle cells (SMCs) and ensheathing pericytes (EPs), also named as terminal vascular SMCs, revealed similar calcium dynamics in vivo. In contrast, calcium signals in capillary pericytes (CPs) were irregular, higher in frequency, and occurred in cellular microdomains. In the absence of the vessel constricting agent U46619 in acute slices, SMCs and EPs revealed only sparse calcium signals, whereas CPs retained their spontaneous calcium activity. Interestingly, chemogenetic activation of neurons in vivo and acute elevations of extracellular potassium in brain slices strongly decreased calcium activity in CPs. We propose that neuronal activation and an extracellular increase in potassium suppress calcium activity in CPs, likely mediated by Kir2.2 and KATP channels.
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Affiliation(s)
- Chaim Glück
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
| | - Kim David Ferrari
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
| | - Noemi Binini
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
| | - Annika Keller
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
- Department of Neurosurgery, University of ZurichSchlierenSwitzerland
| | - Aiman S Saab
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
| | - Jillian L Stobart
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Rady Faculty of Health Sciences, College of PharmacyWinnipegCanada
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
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Han YS, Delmotte PF, Arteaga GM, Sieck GC. Dynamic cytosolic Ca 2+ and force responses to muscarinic stimulation in airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2021; 321:L91-L101. [PMID: 33908264 DOI: 10.1152/ajplung.00596.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
During agonist stimulation of airway smooth muscle (ASM), agonists such as ACh induce a transient increase in cytosolic Ca2+ concentration ([Ca2+]cyt), which leads to a contractile response [excitation-contraction (E-C) coupling]. Previously, the sensitivity of the contractile response of ASM to elevated [Ca2+]cyt (Ca2+ sensitivity) was assessed as the ratio of maximum force to maximum [Ca2+]cyt. However, this static assessment of Ca2+ sensitivity overlooks the dynamic nature of E-C coupling in ASM. In this study, we simultaneously measured [Ca2+]cyt and isometric force responses to three concentrations of ACh (1, 2.6, and 10 μM). Both maximum [Ca2+]cyt and maximum force responses were ACh concentration dependent, but force increased disproportionately, thereby increasing static Ca2+ sensitivity. The dynamic properties of E-C coupling were assessed in several ways. The temporal delay between the onset of ACh-induced [Ca2+]cyt and onset force responses was not affected by ACh concentration. The rates of rise of the ACh-induced [Ca2+]cyt and force responses increased with increasing ACh concentration. The integral of the phase-loop plot of [Ca2+]cyt and force from onset to steady state also increased with increasing ACh concentration, whereas the rate of relaxation remained unchanged. Although these results suggest an ACh concentration-dependent increase in the rate of cross-bridge recruitment and in the rate of rise of [Ca2+]cyt, the extent of regulatory myosin light-chain (rMLC20) phosphorylation was not dependent on ACh concentration. We conclude that the dynamic properties of [Ca2+]cyt and force responses in ASM are dependent on ACh concentration but reflect more than changes in the extent of rMLC20 phosphorylation.
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Affiliation(s)
- Young-Soo Han
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Philippe F Delmotte
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Grace M Arteaga
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
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Ding S, Zhang J, Yin S, Lu J, Hu M, Du J, Huang J, Shen B. Inflammatory cytokines tumour necrosis factor-α and interleukin-8 enhance airway smooth muscle contraction by increasing L-type Ca 2+ channel expression. Clin Exp Pharmacol Physiol 2018; 46:56-64. [PMID: 30203559 DOI: 10.1111/1440-1681.13030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 08/03/2018] [Accepted: 08/05/2018] [Indexed: 12/15/2022]
Abstract
Inflammation elevates intracellular calcium concentrations ([Ca2+ ]i ) in airway smooth muscle (ASM). The L-type Ca2+ channel (L-VDCC) plays an important role in regulating Ca2+ influx in ASM. However, the role of L-VDCC in the inflammatory cytokine-induced pathology of ASM remains unclear. In the present study, we used calcium imaging and isometric tension measurements to assess the role of L-VDCC in agonist-induced [Ca2+ ]i rise and the associated contractions in mouse ASM, and we used immunoblotting to identify L-VDCC protein expression levels in mouse ASM after exposure to tumour necrosis factor alpha (TNF-α) or interleukin-8 (IL-8). Our results showed that high-K+ - or carbachol-induced contractions of mouse ASM were significantly greater after pretreatment with TNF-α or IL-8 for 24 hours. Both verapamil and nifedipine, L-VDCC inhibitors, abolished this increased contraction induced by TNF-α or IL-8 pretreatment. Moreover, TNF-α treatment enhanced carbachol-induced Ca2+ influx in ASM cells, and this effect was abrogated by verapamil. Additionally, immunoblotting results showed that preincubation of mouse ASM with TNF-α or IL-8 also enhanced L-VDCC protein expression. On the basis of these findings, we concluded that proinflammatory cytokines, such as TNF-α and IL-8, increase the expression level of L-VDCC, which in turn contributes to augmented agonist-induced ASM contractions. This effect of inflammation on L-VDCC expression in ASM may be associated with airway hyper-responsiveness and involved in the development of asthma.
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Affiliation(s)
- Shengang Ding
- Department of Paediatrics, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Jie Zhang
- School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui, China.,Department of Physiology, Third Military Medical University, Chongqing, China
| | - Sheng Yin
- School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui, China
| | - Jingsen Lu
- School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui, China
| | - Min Hu
- Department of Sports and Health, Guangzhou Sport University, Guangzhou, Guangdong, China
| | - Juan Du
- School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui, China
| | - Junhao Huang
- Guangdong Provincial Key Laboratory of Sports and Health Promotion, Scientific Research Center, Guangzhou Sport University, Guangzhou, Guangdong, China
| | - Bing Shen
- School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui, China
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Anaparti V, Pascoe CD, Jha A, Mahood TH, Ilarraza R, Unruh H, Moqbel R, Halayko AJ. Tumor necrosis factor regulates NMDA receptor-mediated airway smooth muscle contractile function and airway responsiveness. Am J Physiol Lung Cell Mol Physiol 2016; 311:L467-80. [PMID: 27371735 DOI: 10.1152/ajplung.00382.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 06/30/2016] [Indexed: 12/25/2022] Open
Abstract
We have shown that N-methyl-d-aspartate receptors (NMDA-Rs) are receptor-operated calcium entry channels in human airway smooth muscle (HASM) during contraction. Tumor necrosis factor (TNF) augments smooth muscle contractility by influencing pathways that regulate intracellular calcium flux and can alter NMDA-R expression and activity in cortical neurons and glial cells. We hypothesized that NMDA-R-mediated Ca(2+) and contractile responses of ASM can be altered by inflammatory mediators, including TNF. In cultured HASM cells, we assessed TNF (10 ng/ml, 48 h) effect on NMDA-R subunit abundance by quantitative PCR, confocal imaging, and immunoblotting. We observed dose- and time-dependent changes in NMDA-R composition: increased obligatory NR1 subunit expression and altered regulatory NR2 and inhibitory NR3 subunits. Measuring intracellular Ca(2+) flux in Fura-2-loaded HASM cultures, we observed that TNF exposure enhanced cytosolic Ca(2+) mobilization and changed the temporal pattern of Ca(2+) flux in individual myocytes induced by NMDA, an NMDA-R selective analog of glutamate. We measured airway responses to NMDA in murine thin-cut lung slices (TCLS) from allergen-naive animals and observed significant airway contraction. However, NMDA acted as a bronchodilator in TCLS from house dust mice-challenged mice and in allergen-naive TCLS subjected to TNF exposure. All contractile or bronchodilator responses were blocked by a selective NMDA-R antagonist, (2R)-amino-5-phosphonopentanoate, and bronchodilator responses were prevented by N(G)-nitro-l-arginine methyl ester (nitric oxide synthase inhibitor) or indomethacin (cyclooxygenase inhibitor). Collectively, we show that TNF augments NMDA-R-mediated Ca(2+) mobilization in HASM cells, whereas in multicellular TCLSs allergic inflammation and TNF exposure leads to NMDA-R-mediated bronchodilation. These findings reveal the unique contribution of ionotrophic NMDA-R to airway hyperreactivity.
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Affiliation(s)
- Vidyanand Anaparti
- Department of Immunology, University of Manitoba, Winnipeg, Canada; Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, Canada; Department of Internal Medicine, University of Manitoba, Winnipeg, Canada; and
| | - Christopher D Pascoe
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada; Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
| | - Aruni Jha
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada; Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
| | - Thomas H Mahood
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada; Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
| | - Ramses Ilarraza
- Department of Immunology, University of Manitoba, Winnipeg, Canada
| | - Helmut Unruh
- Department of Internal Medicine, University of Manitoba, Winnipeg, Canada; and Section of Thoracic Surgery, University of Manitoba, Winnipeg, Canada
| | - Redwan Moqbel
- Department of Immunology, University of Manitoba, Winnipeg, Canada; Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
| | - Andrew J Halayko
- Department of Immunology, University of Manitoba, Winnipeg, Canada; Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada; Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, Canada; Department of Internal Medicine, University of Manitoba, Winnipeg, Canada; and
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Toussaint F, Charbel C, Allen BG, Ledoux J. Vascular CaMKII: heart and brain in your arteries. Am J Physiol Cell Physiol 2016; 311:C462-78. [PMID: 27306369 DOI: 10.1152/ajpcell.00341.2015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 06/14/2016] [Indexed: 01/02/2023]
Abstract
First characterized in neuronal tissues, the multifunctional calcium/calmodulin-dependent protein kinase II (CaMKII) is a key signaling component in several mammalian biological systems. Its unique capacity to integrate various Ca(2+) signals into different specific outcomes is a precious asset to excitable and nonexcitable cells. Numerous studies have reported roles and mechanisms involving CaMKII in brain and heart tissues. However, corresponding functions in vascular cell types (endothelium and vascular smooth muscle cells) remained largely unexplored until recently. Investigation of the intracellular Ca(2+) dynamics, their impact on vascular cell function, the regulatory processes involved and more recently the spatially restricted oscillatory Ca(2+) signals and microdomains triggered significant interest towards proteins like CaMKII. Heteromultimerization of CaMKII isoforms (four isoforms and several splice variants) expands this kinase's peculiar capacity to decipher Ca(2+) signals and initiate specific signaling processes, and thus controlling cellular functions. The physiological functions that rely on CaMKII are unsurprisingly diverse, ranging from regulating contractile state and cellular proliferation to Ca(2+) homeostasis and cellular permeability. This review will focus on emerging evidence of CaMKII as an essential component of the vascular system, with a focus on the kinase isoform/splice variants and cellular system studied.
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Affiliation(s)
- Fanny Toussaint
- Research Center, Montreal Heart Institute, Montreal, Quebec, Canada; Department of Molecular and Integrative Physiology, Université de Montréal, Montreal Quebec, Canada
| | - Chimène Charbel
- Research Center, Montreal Heart Institute, Montreal, Quebec, Canada; Department of Pharmacology, Université de Montréal, Montreal Quebec, Canada
| | - Bruce G Allen
- Research Center, Montreal Heart Institute, Montreal, Quebec, Canada; Department of Medicine, Université de Montréal, Montreal Quebec, Canada; and Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal Quebec, Canada
| | - Jonathan Ledoux
- Research Center, Montreal Heart Institute, Montreal, Quebec, Canada; Department of Medicine, Université de Montréal, Montreal Quebec, Canada; and
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Donovan C, Seow HJ, Royce SG, Bourke JE, Vlahos R. Alteration of Airway Reactivity and Reduction of Ryanodine Receptor Expression by Cigarette Smoke in Mice. Am J Respir Cell Mol Biol 2015; 53:471-8. [DOI: 10.1165/rcmb.2014-0400oc] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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10
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Thompson MA, Prakash YS, Pabelick CM. Arachidonate-regulated Ca(2+) influx in human airway smooth muscle. Am J Respir Cell Mol Biol 2014; 51:68-76. [PMID: 24471656 DOI: 10.1165/rcmb.2013-0144oc] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Plasma membrane Ca(2+) influx, especially store-operated Ca(2+) entry triggered by sarcoplasmic reticulum (SR) Ca(2+) release, is a key component of intracellular calcium concentration ([Ca(2+)]i) regulation in airway smooth muscle (ASM). Agonist-induced Ca(2+) oscillations in ASM that involve both influx and SR mechanisms have been previously demonstrated. In nonexcitable cells, [Ca(2+)]i oscillations involve Ca(2+) influx via arachidonic acid (AA) -stimulated channels, which show similarities to store-operated Ca(2+) entry, although their molecular identity remains undetermined. Little is known about AA-regulated Ca(2+) channels or their regulation in ASM. In enzymatically dissociated human ASM cells loaded with the Ca(2+) indicator, fura-2, AA (1-10 μM) triggered [Ca(2+)]i oscillations that were inhibited by removal of extracellular Ca(2+). Other fatty acids, such as the diacylglycerol analog, 1-oleoyl-2-acetyl-SN-glycerol, oleic acid, and palmitic acid (10 μM each), failed to elicit similar [Ca(2+)]i responses. Preincubation with LaCl3 (1 μM or 1 mM) inhibited AA-induced oscillations. Inhibition of receptor-operated channels (SKF96,365 [10 μM]), lipoxygenase (zileuton [10 μM]), or cyclooxygenase (indomethacin [10 μM]) did not affect oscillation parameters. Inhibition of SR Ca(2+) release (ryanodine [10 μM] or inositol 1,4,5-trisphosphate receptor inhibitor, xestospongin C [1 μM]) decreased [Ca(2+)]i oscillation frequency and amplitude. Small interfering RNA against caveolin-1, stromal interaction molecule 1, or Orai3 (20 nM each) reduced the frequency and amplitude of AA-induced [Ca(2+)]i oscillations. In ASM cells derived from individuals with asthma, AA increased oscillation amplitude, but not frequency. These results are highly suggestive of a novel AA-mediated Ca(2+)-regulatory mechanism in human ASM, reminiscent of agonist-induced oscillations. Given the role of AA in ASM intracellular signaling, especially with inflammation, AA-regulated Ca(2+) channels could potentially contribute to increased [Ca(2+)]i in diseases such asthma.
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Jia L, Delmotte P, Aravamudan B, Pabelick CM, Prakash YS, Sieck GC. Effects of the inflammatory cytokines TNF-α and IL-13 on stromal interaction molecule-1 aggregation in human airway smooth muscle intracellular Ca(2+) regulation. Am J Respir Cell Mol Biol 2014; 49:601-8. [PMID: 23713409 DOI: 10.1165/rcmb.2013-0040oc] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Inflammation elevates intracellular Ca(2+) ([Ca(2+)]i) concentrations in airway smooth muscle (ASM). Store-operated Ca(2+) entry (SOCE) is an important source of [Ca(2+)]i mediated by stromal interaction molecule-1 (STIM1), a sarcoplasmic reticulum (SR) protein. In transducing SR Ca(2+) depletion, STIM1 aggregates to form puncta, thereby activating SOCE via interactions with a Ca(2+) release-activated Ca(2+) channel protein (Orai1) in the plasma membrane. We hypothesized that STIM1 aggregation is enhanced by inflammatory cytokines, thereby augmenting SOCE in human ASM cells. We used real-time fluorescence microscopic imaging to assess the dynamics of STIM1 aggregation and SOCE after exposure to TNF-α or IL-13 in ASM cells overexpressing yellow fluorescent protein-tagged wild-type STIM1 (WT-STIM1) and STIM1 mutants lacking the Ca(2+)-sensing EF-hand (STIM1-D76A), or lacking the cytoplasmic membrane binding site (STIM1ΔK). STIM1 aggregation was analyzed by monitoring puncta size during the SR Ca(2+) depletion induced by cyclopiazonic acid (CPA). We found that puncta size was increased in cells expressing WT-STIM1 after CPA. However, STIM1-D76A constitutively formed puncta, whereas STIM1ΔK failed to form puncta. Furthermore, cytokines increased basal WT-STIM1 puncta size, and the SOCE triggered by SR Ca(2+) depletion was increased in cells expressing WT-STIM1 or STIM1-D76A. Meanwhile, SOCE in cells expressing STIM1ΔK and STIM1 short, interfering RNA (siRNA) was decreased. Similarly, in cells overexpressing STIM1, the siRNA knockdown of Orai1 blunted SOCE. However, exposure to cytokines increased SOCE in all cells, increased basal [Ca(2+)]i, and decreased SR Ca(2+) content. These data suggest that cytokines induce a constitutive increase in STIM1 aggregation that contributes to enhanced SOCE in human ASM after inflammation. Such effects of inflammation on STIM1 aggregations may contribute to airway hyperresponsiveness.
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Affiliation(s)
- Li Jia
- 1 Department of Physiology and Biomedical Engineering, and
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12
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Grim KJ, Abcejo AJ, Barnes A, Sathish V, Smelter DF, Ford GC, Thompson MA, Prakash YS, Pabelick CM. Caveolae and propofol effects on airway smooth muscle. Br J Anaesth 2012; 109:444-53. [PMID: 22542538 DOI: 10.1093/bja/aes130] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The i.v. anaesthetic propofol produces bronchodilatation. Airway relaxation involves reduced intracellular Ca(2+) ([Ca(2+)](i)) in airway smooth muscle (ASM) and lipid rafts (caveolae), and constitutional caveolin proteins regulate [Ca(2+)](i). We postulated that propofol-induced bronchodilatation involves caveolar disruption. METHODS Caveolar fractions of human ASM cells were tested for propofol content. [Ca(2+)](i) responses of ASM cells loaded with fura-2 were performed in the presence of 10 µM histamine with and without clinically relevant concentrations of propofol (10 and 30 μM and intralipid control). Effects on sarcoplasmic reticulum (SR) Ca(2+) release were evaluated in zero extracellular Ca(2+) using the blockers Xestospongin C and ryanodine. Store-operated Ca(2+) entry (SOCE) after SR depletion was evaluated using established techniques. The role of caveolin-1 in the effect of propofol was tested using small interference RNA (siRNA) suppression. Changes in intracellular signalling cascades relevant to [Ca(2+)](i) and force regulation were also evaluated. RESULTS Propofol was present in ASM caveolar fractions in substantial concentrations. Exposure to 10 or 30 µM propofol form decreased [Ca(2+)](i) peak (but not plateau) responses to histamine by ~40%, an effect persistent in zero extracellular Ca(2+). Propofol effects were absent in caveolin-1 siRNA-transfected cells. Inhibition of ryanodine receptors prevented propofol effects on [Ca(2+)](i), while propofol blunted [Ca(2+)](i) responses to caffeine. Propofol reduced SOCE, an effect also prevented by caveolin-1 siRNA. Propofol effects were associated with decreased caveolin-1 expression and extracellular signal-regulated kinase phosphorylation. CONCLUSIONS These novel data suggest a role for caveolae (specifically caveolin-1) in propofol-induced bronchodilatation. Due to its lipid nature, propofol may transiently disrupt caveolar regulation, thus altering ASM [Ca(2+)](i).
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Affiliation(s)
- K J Grim
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905, USA
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13
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Sathish V, Abcejo AJ, Thompson MA, Sieck GC, Prakash YS, Pabelick CM. Caveolin-1 regulation of store-operated Ca(2+) influx in human airway smooth muscle. Eur Respir J 2012; 40:470-8. [PMID: 22241747 DOI: 10.1183/09031936.00090511] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Caveolae, plasma membrane invaginations with constitutive caveolin proteins, harbour proteins involved in intracellular calcium ([Ca(2+)](i)) regulation. In human airway smooth muscle (ASM), store-operated Ca(2+) entry (SOCE) is a key component of [Ca(2+)](i) regulation, and contributes to increased [Ca(2+)](i) in inflammation. SOCE involves proteins Orai1 and stromal interaction molecule (STIM)1. We investigated the link between caveolae, SOCE and inflammation in ASM. [Ca(2+)](i) was measured in human ASM cells using fura-2. Small interference RNA (siRNA) or overexpression vectors were used to alter expression of caveolin-1 (Cav-1), Orai1 or STIM1. Tumour necrosis factor (TNF)-α was used as a representative pro-inflammatory cytokine. TNF-α increased SOCE following sarcoplasmic reticulum Ca(2+) depletion, and increased whole-cell and caveolar Orai1 (but only intracellular STIM1). Cav-1 siRNA decreased caveolar and whole-cell Orai1 (but not STIM1) expression, and blunted SOCE, even in the presence of TNF-α. STIM1 overexpression substantially enhanced SOCE: an effect only partially reversed by Cav-1 siRNA. In contrast, Orai1 siRNA substantially blunted SOCE even in the presence of TNF-α. Cav-1 overexpression significantly increased Orai1 expression and SOCE, especially in the presence of TNF-α. These results demonstrate that caveolar expression and regulation of proteins such as Orai1 are important for [Ca(2+)](i) regulation in human ASM cells and its modulation during inflammation.
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14
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Sathish V, Abcejo AJ, VanOosten SK, Thompson MA, Prakash YS, Pabelick CM. Caveolin-1 in cytokine-induced enhancement of intracellular Ca(2+) in human airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2011; 301:L607-14. [PMID: 21803870 DOI: 10.1152/ajplung.00019.2011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Diseases such as asthma are characterized by airway hyperresponsiveness. Enhanced airway smooth muscle (ASM) intracellular Ca(2+) ([Ca(2+)](i)) response to agonist stimulation leading to increased airway constriction has been suggested to contribute to airway hyperresponsiveness. Caveolae are flask-shaped plasma membrane invaginations that express the scaffolding protein caveolin and contain multiple proteins important in [Ca(2+)](i) signaling (e.g., agonist receptors, ion channels). We recently demonstrated that caveolae and caveolin-1 are important in [Ca(2+)](i) regulation in human ASM. Proinflammatory cytokines such as tumor necrosis factor (TNF)-α and interleukin (IL)-13 modulate [Ca(2+)](i) in ASM. We hypothesized that cytokine upregulation of caveolar signaling in ASM contributes to enhanced agonist-induced [Ca(2+)](i) in inflammation. Enzymatically dissociated human ASM cells were exposed to medium (control), 20 ng/ml TNF-α, or 50 ng/ml IL-13 for 24 h. Caveolae-enriched membrane fractions displayed substantial increase in caveolin-1 and -2 expressions by TNF-α and IL-13. Transfection with caveolin-1-mRed DNA substantially accelerated and increased plasma membrane caveolin-1 expression by TNF-α and to a lesser extent by IL-13. Caveolin-1 enhancement was inhibited by nuclear factor-κB and mitogen-activated protein kinase inhibitors. In fura 2-loaded ASM cells, [Ca(2+)](i) responses to 1 μM ACh, 10 μM histamine, or 10 nM bradykinin were all exaggerated by TNF-α as well as IL-13 exposure. However, disruption of caveolae using caveolin-1 suppression via small-interfering RNA resulted in significant blunting of agonist-induced [Ca(2+)](i) responses of vehicle and TNF-α-exposed cells. These functional data were correlated to the presence of TNFR(1) receptor (but not the IL-4/IL-13 receptor) within caveolae. Overall, these results indicate that caveolin-1 plays an important role in airway inflammation by modulating the effect of specific cytokines on [Ca(2+)](i).
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15
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Espinosa-Tanguma R, O'Neil C, Chrones T, Pickering JG, Sims SM. Essential role for calcium waves in migration of human vascular smooth muscle cells. Am J Physiol Heart Circ Physiol 2011; 301:H315-23. [PMID: 21572011 DOI: 10.1152/ajpheart.00355.2010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vascular smooth muscle cell (SMC) migration is characterized by extension of the lamellipodia at the leading edge, lamellipodial attachment to substrate, and release of the rear (uropod) of the cell, all of which enable forward movement. However, little is known regarding the role of intracellular cytosolic Ca(2+) concentration ([Ca(2+)](i)) in coordinating these distinct activities of migrating SMCs. The objective of our study was to determine whether regional changes of Ca(2+) orchestrate the migratory cycle in human vascular SMCs. We carried out Ca(2+) imaging using digital fluorescence microscopy of fura-2 loaded human smooth muscle cells. We found that motile SMCs exhibited Ca(2+) waves that characteristically swept from the rear of polarized cells toward the leading edge. Ca(2+) waves were less evident in nonpolarized, stationary cells, although acute stimulation of these SMCs with the agonists platelet-derived growth factor-BB or histamine could elicit transient rise of [Ca(2+)](i). To investigate a role for Ca(2+) waves in the migratory cycle, we loaded cells with the Ca(2+) chelator BAPTA, which abolished Ca(2+) waves and significantly reduced retraction, supporting a causal role for Ca(2+) in initiation of retraction. However, lamellipod motility was still evident in BAPTA-loaded cells. The incidence of Ca(2+) oscillations was reduced when Ca(2+) release from intracellular stores was disrupted with the sarcoplasmic reticulum Ca(2+)-ATPase inhibitor thapsigargin or by treatment with the inositol 1,4,5-trisphosphate receptor blocker 2-aminoethoxy-diphenyl borate or xestospongin C, implicating Ca(2+) stores in generation of waves. We conclude that Ca(2+) waves are essential for migration of human vascular SMCs and can encode cell polarity.
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Affiliation(s)
- Ricardo Espinosa-Tanguma
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
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16
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Meuchel LW, Stewart A, Smelter DF, Abcejo AJ, Thompson MA, Zaidi SIA, Martin RJ, Prakash YS. Neurokinin-neurotrophin interactions in airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2011; 301:L91-8. [PMID: 21515660 DOI: 10.1152/ajplung.00320.2010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Neurally derived tachykinins such as substance P (SP) play a key role in modulating airway contractility (especially with inflammation). Separately, the neurotrophin brain-derived neurotrophic factor (BDNF; potentially derived from nerves as well as airway smooth muscle; ASM) and its tropomyosin-related kinase receptor, TrkB, are involved in enhanced airway contractility. In this study, we hypothesized that neurokinins and neurotrophins are linked in enhancing intracellular Ca(2+) concentration ([Ca(2+)](i)) regulation in ASM. In rat ASM cells, 24 h exposure to 10 nM SP significantly increased BDNF and TrkB expression (P < 0.05). Furthermore, [Ca(2+)](i) responses to 1 μM ACh as well as BDNF (30 min) effects on [Ca(2+)](i) regulation were enhanced by prior SP exposure, largely via increased Ca(2+) influx (P < 0.05). The enhancing effect of SP on BDNF signaling was blunted by the neurokinin-2 receptor antagonist MEN-10376 (1 μM, P < 0.05) to a greater extent than the neurokinin-1 receptor antagonist RP-67580 (5 nM). Chelation of extracellular BDNF (chimeric TrkB-F(c); 1 μg/ml), as well as tyrosine kinase inhibition (100 nM K252a), substantially blunted SP effects (P < 0.05). Overnight (24 h) exposure of ASM cells to 50% oxygen increased BDNF and TrkB expression and potentiated both SP- and BDNF-induced enhancement of [Ca(2+)](i) (P < 0.05). These results suggest a novel interaction between SP and BDNF in regulating agonist-induced [Ca(2+)](i) regulation in ASM. The autocrine mechanism we present here represents a new area in the development of bronchoconstrictive reflex response and airway hyperreactive disorders.
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Affiliation(s)
- Lucas W Meuchel
- Department of Physiology & Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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17
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Wang IY, Bai Y, Sanderson MJ, Sneyd J. A mathematical analysis of agonist- and KCl-induced Ca(2+) oscillations in mouse airway smooth muscle cells. Biophys J 2010; 98:1170-81. [PMID: 20371316 DOI: 10.1016/j.bpj.2009.12.4273] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Revised: 12/02/2009] [Accepted: 12/03/2009] [Indexed: 10/24/2022] Open
Abstract
Airway hyperresponsiveness is a major characteristic of asthma and is generally ascribed to excessive airway narrowing associated with the contraction of airway smooth muscle cells (ASMCs). ASMC contraction is initiated by a rise in intracellular calcium concentration ([Ca(2+)](i)), observed as oscillatory Ca(2+) waves that can be induced by either agonist or high extracellular K(+) (KCl). In this work, we present a model of oscillatory Ca(2+) waves based on experimental data that incorporate both the inositol trisphosphate receptor and the ryanodine receptor. We then combined this Ca(2+) model and our modified actin-myosin cross-bridge model to investigate the role and contribution of oscillatory Ca(2+) waves to contractile force generation in mouse ASMCs. The model predicts that: 1), the difference in behavior of agonist- and KCl-induced Ca(2+) waves results principally from the fact that the sarcoplasmic reticulum is depleted during agonist-induced oscillations, but is overfilled during KCl-induced oscillations; 2), regardless of the order in which agonist and KCl are added into the cell, the resulting [Ca(2+)](i) oscillations will always be the short-period, agonist-induced-like oscillations; and 3), both the inositol trisphosphate receptor and the ryanodine receptor densities are higher toward one end of the cell. In addition, our results indicate that oscillatory Ca(2+) waves generate less contraction than whole-cell Ca(2+) oscillations induced by the same agonist concentration. This is due to the spatial inhomogeneity of the receptor distributions.
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Affiliation(s)
- Inga Y Wang
- Department of Mathematics, University of Auckland, Auckland, New Zealand
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18
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Arvizo RR, Miranda OR, Thompson MA, Pabelick CM, Bhattacharya R, Robertson JD, Rotello VM, Prakash Y, Mukherjee P. Effect of nanoparticle surface charge at the plasma membrane and beyond. NANO LETTERS 2010; 10:2543-8. [PMID: 20533851 PMCID: PMC2925219 DOI: 10.1021/nl101140t] [Citation(s) in RCA: 405] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Herein, we demonstrate that the surface charge of gold nanoparticles (AuNPs) plays a critical role in modulating membrane potential of different malignant and nonmalignant cell types and subsequent downstream intracellular events. The findings presented here describe a novel mechanism for cell-nanoparticle interactions and AuNP uptake: modulation of membrane potential and its effect on intracellular events. These studies will help understand the biology of cell-nanoparticle interactions and facilitate the engineering of nanoparticles for specific intracellular targets.
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Affiliation(s)
- Rochelle R. Arvizo
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Oscar R. Miranda
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003
| | - Michael A. Thompson
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Christina M. Pabelick
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN 55905
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Resham Bhattacharya
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - J. David Robertson
- Department of Chemistry and University of Missouri Research Reactor, University of Missouri, Columbia, MO 65211
| | | | - Y.S. Prakash
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN 55905
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Priyabrata Mukherjee
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905
- Mayo Clinic Cancer Center, Mayo Clinic College of Medicine, Rochester, MN 55905
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19
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Abstract
The sarcoplasmic reticulum (SR) of smooth muscles presents many intriguing facets and questions concerning its roles, especially as these change with development, disease, and modulation of physiological activity. The SR's function was originally perceived to be synthetic and then that of a Ca store for the contractile proteins, acting as a Ca amplification mechanism as it does in striated muscles. Gradually, as investigators have struggled to find a convincing role for Ca-induced Ca release in many smooth muscles, a role in controlling excitability has emerged. This is the Ca spark/spontaneous transient outward current coupling mechanism which reduces excitability and limits contraction. Release of SR Ca occurs in response to inositol 1,4,5-trisphosphate, Ca, and nicotinic acid adenine dinucleotide phosphate, and depletion of SR Ca can initiate Ca entry, the mechanism of which is being investigated but seems to involve Stim and Orai as found in nonexcitable cells. The contribution of the elemental Ca signals from the SR, sparks and puffs, to global Ca signals, i.e., Ca waves and oscillations, is becoming clearer but is far from established. The dynamics of SR Ca release and uptake mechanisms are reviewed along with the control of luminal Ca. We review the growing list of the SR's functions that still includes Ca storage, contraction, and relaxation but has been expanded to encompass Ca homeostasis, generating local and global Ca signals, and contributing to cellular microdomains and signaling in other organelles, including mitochondria, lysosomes, and the nucleus. For an integrated approach, a review of aspects of the SR in health and disease and during development and aging are also included. While the sheer versatility of smooth muscle makes it foolish to have a "one model fits all" approach to this subject, we have tried to synthesize conclusions wherever possible.
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Affiliation(s)
- Susan Wray
- Department of Physiology, School of Biomedical Sciences, University of Liverpool, Liverpool, Merseyside L69 3BX, United Kingdom.
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20
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Delmotte P, Sanderson MJ. Effects of formoterol on contraction and Ca2+ signaling of mouse airway smooth muscle cells. Am J Respir Cell Mol Biol 2009; 42:373-81. [PMID: 19502388 DOI: 10.1165/rcmb.2008-0403oc] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Formoterol, a long-acting beta(2)-receptor agonist, is used to relieve bronchial constriction. However, formoterol is often a racemic formulation, and contains both (R,R)- and (S,S)-enantiomers. Because the activity of each isomer is poorly defined, the mechanisms by which formoterol relaxes smooth muscle cells (SMCs) of intrapulmonary airways are not well understood. Consequently, we compared the effects of (S,S)-, (R,R)-, and racemic formoterol, as well as (R)-albuterol, on the contraction and Ca(2+) signaling of airway SMCs in mouse lung slices with phase-contrast and confocal microscopy. Small airways were contracted with methacholine and the associated SMCs displayed sustained Ca(2+) oscillations and an increase in Ca(2+) sensitivity. These contracted airways displayed a substantial, concentration-dependent relaxation in response to (R,R)-formoterol. Racemic formoterol had a similar potency as (R,R)-formoterol for relaxing airways. By contrast, (S,S)-formoterol only induced a small relaxation. In conjunction with relaxation, (R,R)- and racemic formoterol stopped and decreased the methacholine-induced Ca(2+) oscillations and Ca(2+) sensitivity of the SMCs, respectively, whereas (S,S)-formoterol only decreased the Ca(2+) sensitivity. In these studies, (R,R)- and racemic formoterol had a similar, but much greater, potency than (R)-albuterol for relaxing mice airways. This action was quickly initiated at high concentrations by decreasing the frequency of Ca(2+) oscillations, but was more usually mediated at lower concentrations by decreasing the Ca(2+) sensitivity of the SMCs.
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Affiliation(s)
- Philippe Delmotte
- Department of Physiology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA
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21
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Sathish V, Leblebici F, Kip SN, Thompson MA, Pabelick CM, Prakash YS, Sieck GC. Regulation of sarcoplasmic reticulum Ca2+ reuptake in porcine airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2008; 294:L787-96. [PMID: 18245264 DOI: 10.1152/ajplung.00461.2007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Regulation of intracellular Ca(2+) concentration ([Ca(2+)](i)) in airway smooth muscle (ASM) during agonist stimulation involves sarcoplasmic reticulum (SR) Ca(2+) release and reuptake. The sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) is key to replenishment of SR Ca(2+) stores. We examined regulation of SERCA in porcine ASM: our hypothesis was that the regulatory protein phospholamban (PLN) and the calmodulin (CaM)-CaM kinase (CaMKII) pathway (both of which are known to regulate SERCA in cardiac muscle) play a role. In porcine ASM microsomes, we examined the expression and extent of PLN phosphorylation after pharmacological inhibition of CaM (with W-7) vs. CaMKII (with KN-62/KN-93) and found that PLN is phosphorylated by CaMKII. In parallel experiments using enzymatically dissociated single ASM cells loaded with the Ca(2+) indicator fluo 3 and imaged using fluorescence microscopy, we measured the effects of PLN small interfering RNA, W-7, and KN-62 on [Ca(2+)](i) responses to ACh and direct SR stimulation. PLN small interfering RNA slowed the rate of fall of [Ca(2+)](i) transients to 1 microM ACh, as did W-7 and KN-62. The two inhibitors additionally slowed reuptake in the absence of PLN. In other cells, preexposure to W-7 or KN-62 did not prevent initiation of ACh-induced [Ca(2+)](i) oscillations (which were previously shown to result from repetitive SR Ca(2+) release/reuptake). However, when ACh-induced [Ca(2+)](i) oscillations reached steady state, subsequent exposure to W7 or KN-62 decreased oscillation frequency and amplitude and slowed the fall time of [Ca(2+)](i) transients, suggesting SERCA inhibition. Exposure to W-7 completely abolished ongoing ACh-induced [Ca(2+)](i) oscillations in some cells. Preexposure to W-7 or KN-62 did not affect caffeine-induced SR Ca(2+) release, indicating that ryanodine receptor channels were not directly inhibited. These data indicate that, in porcine ASM, the CaM-CaMKII pathway regulates SR Ca(2+) reuptake, potentially through altered PLN phosphorylation.
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Affiliation(s)
- Venkatachalem Sathish
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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22
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Kovac JR, Chrones T, Sims SM. Temporal and spatial dynamics underlying capacitative calcium entry in human colonic smooth muscle. Am J Physiol Gastrointest Liver Physiol 2008; 294:G88-98. [PMID: 17975132 DOI: 10.1152/ajpgi.00305.2007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Following smooth muscle excitation and contraction, depletion of intracellular Ca(2+) stores activates capacitative Ca(2+) entry (CCE) to replenish stores and sustain cytoplasmic Ca(2+) (Ca(2+)(i)) elevations. The objectives of the present study were to characterize CCE and the Ca(2+)(i) dynamics underlying human colonic smooth muscle contraction by using tension recordings, fluorescent Ca(2+)-indicator dyes, and patch-clamp electrophysiology. The neurotransmitter acetylcholine (ACh) contracted tissue strips and, in freshly isolated colonic smooth muscle cells (SMCs), caused elevation of Ca(2+)(i) as well as activation of nonselective cation currents. To deplete Ca(2+)(i) stores, the sarcoplasmic reticulum Ca(2+)-ATPase (SERCA) inhibitors thapsigargin and cyclopiazonic acid were added to a Ca(2+)-free bathing solution. Under these conditions, addition of extracellular Ca(2+) (3 mM) elicited increased tension that was inhibited by the cation channel blockers SKF-96365 (10 microM) and lanthanum (100 microM), suggestive of CCE. In a separate series of experiments on isolated SMCs, SERCA inhibition generated a gradual and sustained inward current. When combined with high-speed Ca(2+)-imaging techniques, the CCE-evoked rise of Ca(2+)(i) was associated with inward currents carrying Ca(2+) that were inhibited by SKF-96365. Regional specializations in Ca(2+) influx and handling during CCE were observed. Distinct "hotspot" regions of Ca(2+) rise and plateau were evident in 70% of cells, a feature not previously recognized in smooth muscle. We propose that store-operated Ca(2+) entry occurs in hotspots contributing to localized Ca(2+) elevations in human colonic smooth muscle.
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Affiliation(s)
- Jason R Kovac
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1, Canada
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Balasubramanian L, Sham JSK, Yip KP. Calcium signaling in vasopressin-induced aquaporin-2 trafficking. Pflugers Arch 2007; 456:747-54. [PMID: 17957381 DOI: 10.1007/s00424-007-0371-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 10/03/2007] [Accepted: 10/08/2007] [Indexed: 01/06/2023]
Abstract
It has been the general consensus that cAMP-mediated PKA-dependent phosphorylation of aquaporin-2 is the primary mechanism of vasopressin to regulate osmotic water permeability in kidney collecting duct. By using laser scanning confocal microscopy to monitor [Ca2+]i and apical exocytosis in individual cells of inner medullary collecting duct, we have demonstrated that vasopressin also triggers intracellular Ca2+ mobilization, which is coupled to apical exocytotic insertion of aquaporin-2. Vasopressin-induced Ca2+ mobilization is in the form of oscillations, which involves both intracellular Ca2+ release from ryanodine-gated Ca2+ stores and extracellular Ca2+ influx via capacitative calcium entry. Each individual cell operates as an independent calcium oscillator with time variance in frequency and amplitude. Vasopressin-induced Ca2+ mobilization is mediated by cAMP, but is independent of PKA. Exogenous cAMP analog (8-pCPT-2'-O-Me-cAMP), which activates Epac (exchange protein directly activated by cAMP), but not PKA, triggers Ca2+ mobilization and apical exocytosis. These observations suggest that activation of Epac by cAMP may also contribute to the action of vasopressin in regulating osmotic water permeability. There are multiple plausible candidates for downstream effectors of vasopressin-induced Ca2+ signal including calmodulin, myosin light chain kinase, calmodulin kinase II, and calcineurin. All of them have been implicated in the regulation of aquaporin-2 trafficking and/or water permeability.
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Affiliation(s)
- Lavanya Balasubramanian
- Department of Molecular Pharmacology and Physiology, College of Medicine, University of South Florida, Tampa, FL 33612, USA
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Prakash YS, Thompson MA, Vaa B, Matabdin I, Peterson TE, He T, Pabelick CM. Caveolins and intracellular calcium regulation in human airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2007; 293:L1118-26. [PMID: 17704188 DOI: 10.1152/ajplung.00136.2007] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Regulation of intracellular Ca(2+) concentration ([Ca(2+)](i)) is a key factor in airway smooth muscle (ASM) tone. In vascular smooth muscle, specialized membrane microdomains (caveolae) expressing the scaffolding protein caveolin-1 are thought to facilitate cellular signal transduction. In human ASM cells, we tested the hypothesis that caveolae mediate Ca(2+) responses to agonist stimulation. Fluorescence immunocytochemistry with confocal microscopy, as well as Western blot analysis, was used to determine that agonist receptors (M(3) muscarinic, bradykinin, and histamine) and store-operated Ca(2+) entry (SOCE)-regulatory mechanisms colocalize with caveolin-1. Although caveolin-2 coexpressed with caveolin-1, caveolin-3 was absent. In fura 2-loaded ASM cells, [Ca(2+)](i) responses to 1 microM ACh, 10 microM histamine, and 10 nM bradykinin, as well as SOCE, were attenuated (each to a different extent) after disruption of caveolae by the cholesterol-chelating drug methyl-beta-cyclodextrin. Transfection of ASM cells with 50 nM caveolin-1 small interfering RNA significantly weakened caveolin-1 expression and blunted [Ca(2+)](i) responses to bradykinin and histamine, as well as SOCE, but the response to ACh was less intense. These results indicate that caveolae are present in ASM and that caveolin-1 contributes to regulation of [Ca(2+)](i) responses to agonist.
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Affiliation(s)
- Y S Prakash
- Departments of Anesthesiology, Mayo Clinic College of Medicine, Rochester, Minnesota, USA .
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An S, Bai T, Bates J, Black J, Brown R, Brusasco V, Chitano P, Deng L, Dowell M, Eidelman D, Fabry B, Fairbank N, Ford L, Fredberg J, Gerthoffer W, Gilbert S, Gosens R, Gunst S, Halayko A, Ingram R, Irvin C, James A, Janssen L, King G, Knight D, Lauzon A, Lakser O, Ludwig M, Lutchen K, Maksym G, Martin J, Mauad T, McParland B, Mijailovich S, Mitchell H, Mitchell R, Mitzner W, Murphy T, Paré P, Pellegrino R, Sanderson M, Schellenberg R, Seow C, Silveira P, Smith P, Solway J, Stephens N, Sterk P, Stewart A, Tang D, Tepper R, Tran T, Wang L. Airway smooth muscle dynamics: a common pathway of airway obstruction in asthma. Eur Respir J 2007; 29:834-60. [PMID: 17470619 PMCID: PMC2527453 DOI: 10.1183/09031936.00112606] [Citation(s) in RCA: 279] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Excessive airway obstruction is the cause of symptoms and abnormal lung function in asthma. As airway smooth muscle (ASM) is the effecter controlling airway calibre, it is suspected that dysfunction of ASM contributes to the pathophysiology of asthma. However, the precise role of ASM in the series of events leading to asthmatic symptoms is not clear. It is not certain whether, in asthma, there is a change in the intrinsic properties of ASM, a change in the structure and mechanical properties of the noncontractile components of the airway wall, or a change in the interdependence of the airway wall with the surrounding lung parenchyma. All these potential changes could result from acute or chronic airway inflammation and associated tissue repair and remodelling. Anti-inflammatory therapy, however, does not "cure" asthma, and airway hyperresponsiveness can persist in asthmatics, even in the absence of airway inflammation. This is perhaps because the therapy does not directly address a fundamental abnormality of asthma, that of exaggerated airway narrowing due to excessive shortening of ASM. In the present study, a central role for airway smooth muscle in the pathogenesis of airway hyperresponsiveness in asthma is explored.
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Affiliation(s)
- S.S. An
- Division of Physiology, Dept of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health
| | - T.R. Bai
- James Hogg iCAPTURE Centre, University of British Columbia, Vancouver
| | - J.H.T. Bates
- Vermont Lung Center, University of Vermont College of Medicine, Burlington, VT
| | - J.L. Black
- Dept of Pharmacology, University of Sydney, Sydney
| | - R.H. Brown
- Dept of Anesthesiology and Critical Care medicine, Johns Hopkins Medical Institutions, Baltimore, MD
| | - V. Brusasco
- Dept of Internal Medicine, University of Genoa, Genoa
| | - P. Chitano
- Dept of Paediatrics, Duke University Medical Center, Durham, NC
| | - L. Deng
- Program in Molecular and Integrative Physiological Sciences, Dept of Environmental Health, Harvard School of Public Health
- Bioengineering College, Chongqing University, Chongqing, China
| | - M. Dowell
- Section of Pulmonary and Critical Care Medicine
| | - D.H. Eidelman
- Meakins-Christie Laboratories, Dept of Medicine, McGill University, Montreal
| | - B. Fabry
- Center for Medical Physics and Technology, Erlangen, Germany
| | - N.J. Fairbank
- School of Biomedical Engineering, Dalhousie University, Halifax
| | | | - J.J. Fredberg
- Program in Molecular and Integrative Physiological Sciences, Dept of Environmental Health, Harvard School of Public Health
| | - W.T. Gerthoffer
- Dept of Pharmacology, University of Nevada School of Medicine, Reno, NV
| | | | - R. Gosens
- Dept of Physiology, University of Manitoba, Winnipeg
| | - S.J. Gunst
- Dept of Physiology, Indiana University School of Medicine, Indianapolis, IN
| | - A.J. Halayko
- Dept of Physiology, University of Manitoba, Winnipeg
| | - R.H. Ingram
- Dept of Medicine, Emory University School of Medicine, Atlanta, GA
| | - C.G. Irvin
- Vermont Lung Center, University of Vermont College of Medicine, Burlington, VT
| | - A.L. James
- West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Nedlands
| | - L.J. Janssen
- Dept of Medicine, McMaster University, Hamilton, Canada
| | - G.G. King
- Woolcock Institute of Medical Research, Camperdown
| | - D.A. Knight
- James Hogg iCAPTURE Centre, University of British Columbia, Vancouver
| | - A.M. Lauzon
- Meakins-Christie Laboratories, Dept of Medicine, McGill University, Montreal
| | - O.J. Lakser
- Section of Paediatric Pulmonary Medicine, University of Chicago, Chicago, IL
| | - M.S. Ludwig
- Meakins-Christie Laboratories, Dept of Medicine, McGill University, Montreal
| | - K.R. Lutchen
- Dept of Biomedical Engineering, Boston University, Boston
| | - G.N. Maksym
- School of Biomedical Engineering, Dalhousie University, Halifax
| | - J.G. Martin
- Meakins-Christie Laboratories, Dept of Medicine, McGill University, Montreal
| | - T. Mauad
- Dept of Pathology, Sao Paulo University Medical School, Sao Paulo, Brazil
| | | | - S.M. Mijailovich
- Program in Molecular and Integrative Physiological Sciences, Dept of Environmental Health, Harvard School of Public Health
| | - H.W. Mitchell
- Discipline of Physiology, School of Biomedical, Biomolecular and Chemical Sciences, University of Western Australia, Perth
| | | | - W. Mitzner
- Division of Physiology, Dept of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health
| | - T.M. Murphy
- Dept of Paediatrics, Duke University Medical Center, Durham, NC
| | - P.D. Paré
- James Hogg iCAPTURE Centre, University of British Columbia, Vancouver
| | - R. Pellegrino
- Dept of Respiratory Physiopathology, S. Croce e Carle Hospital, Cuneo, Italy
| | - M.J. Sanderson
- Dept of Physiology, University of Massachusetts Medical School, Worcester, MA
| | - R.R. Schellenberg
- James Hogg iCAPTURE Centre, University of British Columbia, Vancouver
| | - C.Y. Seow
- James Hogg iCAPTURE Centre, University of British Columbia, Vancouver
| | - P.S.P. Silveira
- Dept of Pathology, Sao Paulo University Medical School, Sao Paulo, Brazil
| | - P.G. Smith
- Dept of Paediatrics, School of Medicine, Case Western Reserve University, Cleveland, OH
| | - J. Solway
- Section of Pulmonary and Critical Care Medicine
| | - N.L. Stephens
- Dept of Physiology, University of Manitoba, Winnipeg
| | - P.J. Sterk
- Dept of Pulmonology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - A.G. Stewart
- Dept of Pharmacology, University of Melbourne, Parkville, Australia
| | - D.D. Tang
- Center for Cardiovascular Sciences, Albany Medical College, Albany, NY, USA
| | - R.S. Tepper
- Dept of Paediatrics, Indiana University School of Medicine, Indianapolis, IN
| | - T. Tran
- Dept of Physiology, University of Manitoba, Winnipeg
| | - L. Wang
- Dept of Paediatrics, Duke University Medical Center, Durham, NC
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Dai JM, Kuo KH, Leo JM, Paré PD, van Breemen C, Lee CH. Acetylcholine-Induced Asynchronous Calcium Waves in Intact Human Bronchial Muscle Bundle. Am J Respir Cell Mol Biol 2007; 36:600-8. [PMID: 17170384 DOI: 10.1165/rcmb.2006-0096oc] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Calcium (Ca2+) is an important activator of the contractile machinery in airway smooth muscle (ASM). While agonist-induced Ca2+ signals are well characterized in animal ASM, little is known about what occurs in adult human ASM. In this study, we examined the Ca2+ signal elicited by acetylcholine (ACh) in smooth muscle cells of the intact human bronchial muscle strips obtained from fresh surgical specimens in relation to muscle contraction. We found that ACh induces repetitive Ca2+ waves that spread along the longitudinal axis of individual cells in the intact human bronchial smooth muscle strips. These Ca2+ waves display no apparent synchronization between neighboring cells, and their generation precedes force development. Comparison of the ACh concentration dependence of tissue contraction and selected parameters of the asynchronous Ca2+ waves (ACW) reveals that the graded force generation by ACh-stimulated human bronchial muscle strips is achieved by differential recruitment of cells to initiate Ca2+ waves and by enhancement of the frequency of ACW once the cells are recruited. Furthermore, pharmacologic characterization shows that the ACW are produced by repetitive cycles of SR Ca2+ release via ryanodine-sensitive channels followed by SR Ca2+ reuptake by sarco(endo)plasmic reticulum Ca2+ ATPase. Extracellular Ca2+ entry involving receptor-operated channels/store-operated channels, reverse-mode Na+/Ca2+ exchange, and to a lesser extent L-type voltage-gated Ca2+ channels is required to maintain the ACW. These findings for the first time demonstrate the occurrence and the role of ACW in excitation-contraction coupling in adult human ASM.
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Affiliation(s)
- Jiazhen M Dai
- The James Hogg iCAPTURE Center for Cardiovascular and Pulmonary Research, University of British Columbia, and St. Paul's Hospital, Room 166, 1081 Burrard Street, Vancouver, BC, V6Z 1Y6 Canada
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27
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Silva CLM, Gontijo LS, Noël F. Noradrenaline-induced contraction of mice aorta is enhanced in schistosomiasis. Vascul Pharmacol 2006; 46:122-8. [PMID: 17049461 DOI: 10.1016/j.vph.2006.08.414] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Revised: 06/05/2006] [Accepted: 08/30/2006] [Indexed: 02/07/2023]
Abstract
Schistosomiasis, an intravascular parasitic disease caused by Schistosoma mansoni, is related to alterations of murine vascular reactivity in the mesenteric bed, characterized by an impairment of the l-arginine/NO pathway and an increased potency of 5-hydroxytryptamine. The current study was performed to test the hypothesis that a similar alteration of reactivity also occurs in the aorta and to identify the mechanism behind such an increase. We found that aorta from mice infected with male S. mansoni exhibited an enhanced contraction in response to noradrenaline and 100 mM KCl. The inhibition of nitric oxide synthase increased aortic maximal contraction in response to noradrenaline in both groups, but the effect was less pronounced in infected mice than in control mice. Endothelium-dependent relaxation induced by acetylcholine was also smaller in infected mice compared to control mice, while endothelial-independent relaxation induced by sodium nitroprusside and forskolin was similar in both groups. The inhibition of voltage-dependent L-type Ca(2+) channels reduced the maximal contraction in response to noradrenaline more effectively in infected than in control mice. Conversely the inhibition of K(ATP) channels had a smaller effect in the infected group. As a conclusion, our data indicate that schistosomiasis also alters murine vascular reactivity outside the mesenteric bed, due to a partial impairment of NO signaling, a reduced contribution of K(ATP) channels and an increased Ca(2+) influx through L-type Ca(2+) channels.
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Affiliation(s)
- C L M Silva
- Departamento de Farmacologia Básica e Clínica, ICB, Universidade Federal do Rio de Janeiro, Brazil
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Kip SN, Smelter M, Iyanoye A, Chini EN, Prakash YS, Pabelick CM, Sieck GC. Agonist-induced cyclic ADP ribose production in airway smooth muscle. Arch Biochem Biophys 2006; 452:102-7. [PMID: 16846589 DOI: 10.1016/j.abb.2006.06.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Revised: 06/08/2006] [Accepted: 06/10/2006] [Indexed: 11/22/2022]
Abstract
Cyclic ADP-ribose (cADPR) triggers sarcoplasmic reticulum (SR) Ca(2+) release in airway smooth muscle (ASM). SR Ca(2+) release is an important component of the intracellular Ca(2+) ([Ca(2+)](i)) response of ASM to agonists. Whether cADPR is endogenously produced in ASM during agonist stimulation has not been established. In this study, cADPR production was examined in acutely dissociated porcine ASM cells. ACh stimulation (> or = 1 microM) significantly increased cADPR levels, peaking between 30s and 1 min. This effect was inhibited by M(2) and M(3) muscarinic receptor antagonists. Histamine ((> or = 5 microM) increased cADPR levels to a greater extent than ACh, while diphenhydramine blocked histamine-induced cADPR elevation. Both bradykinin (100 nM) and endothelin-1 (100 nM) also increased cADPR levels to a greater extent than ACh or histamine. These results indicate that in porcine ASM, certain agonists acting via receptors increase cADPR levels. Furthermore, the extent of cADPR responses to agonist varies, possibly reflecting differences in G-protein coupling.
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Affiliation(s)
- Sertac N Kip
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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29
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Yip KP. Epac-mediated Ca(2+) mobilization and exocytosis in inner medullary collecting duct. Am J Physiol Renal Physiol 2006; 291:F882-90. [PMID: 16684923 DOI: 10.1152/ajprenal.00411.2005] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
PKA has traditionally been thought as the binding protein of cAMP for mediating arginine vasopressin (AVP)-regulated osmotic water permeability in kidney collecting duct. It is now known that cAMP also exerts its effects via Epac (exchange protein directly activated by cAMP) and that intracellular Ca(2+) mobilization is necessary for AVP-induced apical exocytosis in inner medullary collecting duct (IMCD). The role of Epac as an effector of cAMP action in addition to PKA was investigated using confocal fluorescence microscopy in perfused IMCD. PKA inhibitors (1 microM H-89 or 10 microM KT-5720) at concentrations known to inhibit aquaporin-2 (AQP2) phosphorylation did not prevent AVP-induced Ca(2+) mobilization and oscillations. Epac-selective cAMP agonist (8-pCPT-2'-O-Me-cAMP) mimicked AVP in triggering Ca(2+) mobilization and oscillations, which was blocked by ryanodine but not by Rp-cAMP (a competitive antagonist of cAMP binding to PKA). 8-pCPT-2'-O-Me-cAMP also triggered apical exocytosis in the presence of a PKA inhibitor. Immunolocalization of AQP2 in perfused IMCD demonstrated that 8-pCPT-2'-O-Me-cAMP induces apical targeting of AQP2 and that AQP2 is abundant in junctional regions of basolateral membrane. Immunofluorescence study also confirmed the presence of Epac (isoform I) in IMCD. These results indicate that activation of Epac by an exogenous cAMP analog triggers intracellular Ca(2+) mobilization and apical exocytotic insertion of AQP2 in IMCD.
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Affiliation(s)
- Kay-Pong Yip
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida 33612, USA.
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30
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Prakash YS, Iyanoye A, Ay B, Mantilla CB, Pabelick CM. Neurotrophin effects on intracellular Ca2+ and force in airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2006; 291:L447-56. [PMID: 16648236 DOI: 10.1152/ajplung.00501.2005] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neurotrophins [e.g., brain-derived neurotrophic factor (BDNF), neurotrophin 4 (NT4)], known to affect neuronal structure and function, are expressed in nonneuronal tissues including the airway. However, their function is unclear. We examined the effect of acute vs. prolonged neurotrophin exposure on regulation of airway smooth muscle (ASM) intracellular Ca(2+) concentration ([Ca(2+)](i)): sarcoplasmic reticulum (SR) Ca(2+) release and Ca(2+) influx (specifically store-operated Ca(2+) entry, SOCE). Human ASM cells were incubated for 30 min in medium (control) or 1 or 10 nM BDNF, NT3, or NT4 (acute exposure) or overnight in 1 nM BDNF, NT3, or NT4 (prolonged exposure) and imaged after loading with the Ca(2+) indicator fura-2 AM. [Ca(2+)](i) responses to ACh, histamine, bradykinin, and caffeine and SOCE following SR Ca(2+) depletion were compared across cell groups. Force measurements were performed in human bronchial strips exposed to neurotrophins. Basal [Ca(2+)](i), peak responses to all agonists, SOCE, and force responses to ACh and histamine were all significantly enhanced by both acute and prolonged BDNF exposure (smaller effect of NT4) but decreased by NT3. Inhibition of the BDNF/NT4 receptor trkB by K252a prevented enhancement of [Ca(2+)](i) responses. ASM cells showed positive immunostaining for BDNF, NT3, NT4, trkB, and trkC (NT3 receptor). These novel data demonstrate that neurotrophins influence ASM [Ca(2+)](i) and force regulation and suggest a potential role for neurotrophins in airway diseases.
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Affiliation(s)
- Y S Prakash
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
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Bergner A, Kellner J, Kemp da Silva A, Gamarra F, Huber RM. Ca2+-signaling in airway smooth muscle cells is altered in T-bet knock-out mice. Respir Res 2006; 7:33. [PMID: 16504082 PMCID: PMC1395308 DOI: 10.1186/1465-9921-7-33] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2005] [Accepted: 02/23/2006] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Airway smooth muscle cells (ASMC) play a key role in bronchial hyperresponsiveness (BHR). A major component of the signaling cascade leading to ASMC contraction is calcium. So far, agonist-induced Ca2+-signaling in asthma has been studied by comparing innate properties of inbred rat or mouse strains, or by using selected mediators known to be involved in asthma. T-bet knock-out (KO) mice show key features of allergic asthma such as a shift towards TH2-lymphocytes and display a broad spectrum of asthma-like histological and functional characteristics. In this study, we aimed at investigating whether Ca2+-homeostasis of ASMC is altered in T-bet KO-mice as an experimental model of asthma. METHODS Lung slices of 100 to 200 microm thickness were obtained from T-bet KO- and wild-type mice. Airway contraction in response to acetylcholine (ACH) was measured by video-microscopy and Ca2+-signaling in single ASMC of lung slices was assessed using two-photon-microscopy. RESULTS Airways from T-bet KO-mice showed increased baseline airway tone (BAT) and BHR compared to wild-type mice. This could be mimicked by incubation of lung slices from wild-type mice with IL-13. The increased BAT was correlated with an increased incidence of spontaneous changes in intracellular Ca2+-concentrations, whereas BHR correlated with higher ACH-induced Ca2+-transients and an increased proportion of ASMC showing Ca2+-oscillations. Emptying intracellular Ca2+-stores using caffeine or cyclopiazonic acid induced higher Ca2+-elevations in ASMC from T-bet KO- compared to wild-type mice. CONCLUSION Altered Ca2+-homeostasis of ASMC contributes to increased BAT and BHR in lung slices from T-bet KO-mice as a murine asthma model. We propose that a higher Ca2+-content of the intracellular Ca2+-stores is involved in the pathophysiology of these changes.
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Affiliation(s)
- Albrecht Bergner
- Pneumology, Medizinische Klinik-Innenstadt, Ludwig-Maximilians-University, Munich, Germany
| | - Julia Kellner
- Pneumology, Medizinische Klinik-Innenstadt, Ludwig-Maximilians-University, Munich, Germany
| | - Anita Kemp da Silva
- Pneumology, Medizinische Klinik-Innenstadt, Ludwig-Maximilians-University, Munich, Germany
| | - Fernando Gamarra
- Pneumology, Medizinische Klinik-Innenstadt, Ludwig-Maximilians-University, Munich, Germany
| | - Rudolf M Huber
- Pneumology, Medizinische Klinik-Innenstadt, Ludwig-Maximilians-University, Munich, Germany
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Perez JF, Sanderson MJ. The frequency of calcium oscillations induced by 5-HT, ACH, and KCl determine the contraction of smooth muscle cells of intrapulmonary bronchioles. ACTA ACUST UNITED AC 2005; 125:535-53. [PMID: 15928401 PMCID: PMC2234076 DOI: 10.1085/jgp.200409216] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Increased resistance of airways or blood vessels within the lung is associated with asthma or pulmonary hypertension and results from contraction of smooth muscle cells (SMCs). To study the mechanisms regulating these contractions, we developed a mouse lung slice preparation containing bronchioles and arterioles and used phase-contrast and confocal microscopy to correlate the contractile responses with changes in [Ca2+]i of the SMCs. The airways are the focus of this study. The agonists, 5-hydroxytrypamine (5-HT) and acetylcholine (ACH) induced a concentration-dependent contraction of the airways. High concentrations of KCl induced twitching of the airway SMCs but had little effect on airway size. 5-HT and ACH induced asynchronous oscillations in [Ca2+]i that propagated as Ca2+ waves within the airway SMCs. The frequency of the Ca2+ oscillations was dependent on the agonist concentration and correlated with the extent of sustained airway contraction. In the absence of extracellular Ca2+ or in the presence of Ni2+, the frequency of the Ca2+ oscillations declined and the airway relaxed. By contrast, KCl induced low frequency Ca2+ oscillations that were associated with SMC twitching. Each KCl-induced Ca2+ oscillation consisted of a large Ca2+ wave that was preceded by multiple localized Ca2+ transients. KCl-induced responses were resistant to neurotransmitter blockers but were abolished by Ni2+ or nifedipine and the absence of extracellular Ca2+. Caffeine abolished the contractile effects of 5-HT, ACH, and KCl. These results indicate that (a) 5-HT and ACH induce airway SMC contraction by initiating Ca2+ oscillations, (b) KCl induces Ca2+ transients and twitching by overloading and releasing Ca2+ from intracellular stores, (c) a sustained, Ni2+-sensitive, influx of Ca2+ mediates the refilling of stores to maintain Ca2+ oscillations and, in turn, SMC contraction, and (d) the magnitude of sustained airway SMC contraction is regulated by the frequency of Ca2+ oscillations.
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Affiliation(s)
- Jose F Perez
- Department of Physiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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Ay B, Iyanoye A, Sieck GC, Prakash YS, Pabelick CM. Cyclic nucleotide regulation of store-operated Ca2+ influx in airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2005; 290:L278-83. [PMID: 16155088 DOI: 10.1152/ajplung.00188.2005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sarcoplasmic reticulum (SR) Ca2+ release and plasma membrane Ca2+ influx are key to intracellular Ca2+ ([Ca2+]i) regulation in airway smooth muscle (ASM). SR Ca2+ depletion triggers influx via store-operated Ca2+ channels (SOCC) for SR replenishment. Several clinically relevant bronchodilators mediate their effect via cyclic nucleotides (cAMP, cGMP). We examined the effect of cyclic nucleotides on SOCC-mediated Ca2+ influx in enzymatically dissociated porcine ASM cells. SR Ca2+ was depleted by 1 microM cyclopiazonic acid in 0 extracellular Ca2+ ([Ca2+]o), nifedipine, and KCl (preventing Ca2+ influx through L-type and SOCC channels). SOCC was then activated by reintroduction of [Ca2+]o and characterized by several techniques. We examined cAMP effects on SOCC by activating SOCC in the presence of 1 microM isoproterenol or 100 microM dibutryl cAMP (cell-permeant cAMP analog), whereas we examined cGMP effects using 1 microM (Z)-1-[N-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate (DETA-NO nitric oxide donor) or 100 microM 8-bromoguanosine 3',5'-cyclic monophosphate (cell-permeant cGMP analog). The role of protein kinases A and G was examined by preexposure to 100 nM KT-5720 and 500 nM KT-5823, respectively. SOCC-mediated Ca2+ influx was dependent on the extent of SR Ca2+ depletion, sensitive to Ni2+ and La3+, but not inhibitors of voltage-gated influx channels. cAMP as well as cGMP potently inhibited Ca2+ influx, predominantly via their respective protein kinases. Additionally, cAMP cross-activation of protein kinase G contributed to SOCC inhibition. These data demonstrate that a Ni2+/La3+-sensitive Ca2+ influx in ASM triggered by SR Ca2+ depletion is inhibited by cAMP and cGMP via a protein kinase mechanism. Such inhibition may play a role in the bronchodilatory response of ASM to clinically relevant drugs (e.g., beta-agonists vs. nitric oxide).
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Affiliation(s)
- Binnaz Ay
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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34
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Bkaily G, El-Bizri N, Nader M, Hazzouri KM, Riopel J, Jacques D, Regoli D, D'Orleans-Juste P, Gobeil F, Avedanian L. Angiotensin II induced increase in frequency of cytosolic and nuclear calcium waves of heart cells via activation of AT1 and AT2 receptors. Peptides 2005; 26:1418-26. [PMID: 15876474 DOI: 10.1016/j.peptides.2005.03.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The aim of this work is to verify if Angiotensin II (Ang II) affects the frequency of spontaneous cytosolic and nuclear Ca2+ waves in chick embryonic cardiomyocytes and if this effect is mediated via the activation of AT1 and/or AT2 receptors. Using the rapid scan technique of confocal microscopy, we observed that Ang II (10(-8)M) increases the frequency of cytosolic and nuclear Ca2+ waves. This effect was accompanied by a decrease in the amplitude of nuclear Ca2+ waves and an absence of effect on the amplitude of cytosolic Ca2+ waves. The effect of the octapeptide on both frequency and amplitude of the nuclear waves was prevented by the AT1 receptor antagonist L158809. However, blockade of the AT2 receptor using the antagonist PD123319 (10(-7)M) only prevented the effect of Ang II on the frequency of Ca2+ waves. Furthermore, the effect was prevented by both a PKC inhibitor (bisindolylmaleimide) and a PKC activator (phorbol 12,13-dibutyrate). In addition, the Ang II effect was not prevented by the blocker of the pacemaker current If. These results demonstrate that Ang II, via the activation of its receptors AT1 and AT2, affects the frequency of spontaneous Ca2+ waves and this effect seems to be mediated by the PKC pathway.
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MESH Headings
- Angiotensin II/antagonists & inhibitors
- Angiotensin II/pharmacology
- Angiotensin II Type 1 Receptor Blockers
- Angiotensin II Type 2 Receptor Blockers
- Animals
- Calcium/antagonists & inhibitors
- Calcium/physiology
- Calcium Signaling/drug effects
- Calcium Signaling/physiology
- Cell Nucleus/drug effects
- Cell Nucleus/metabolism
- Chickens
- Cytosol/drug effects
- Cytosol/metabolism
- Dose-Response Relationship, Drug
- Heart Ventricles/drug effects
- Heart Ventricles/embryology
- Imidazoles/pharmacology
- Indoles/pharmacology
- Maleimides/pharmacology
- Microscopy, Confocal/methods
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/physiology
- Phorbol 12,13-Dibutyrate/pharmacology
- Protein Kinase C/drug effects
- Protein Kinase C/metabolism
- Pyridines/pharmacology
- Receptor, Angiotensin, Type 1/drug effects
- Receptor, Angiotensin, Type 1/physiology
- Receptor, Angiotensin, Type 2/drug effects
- Receptor, Angiotensin, Type 2/physiology
- Tetrazoles/pharmacology
- Time Factors
- Ventricular Function
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Affiliation(s)
- Ghassan Bkaily
- Department of Anatomy & Cell Biology, Faculty of Medicine, Université de Sherbrooke, 3001-12th Avenue North, Sherbrooke, Que., Canada J1H 5N4.
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35
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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.
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Affiliation(s)
- Régent Laporte
- Ferring Research Institute, Inc., Ferring Pharmaceuticals, San Diego, California, USA
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36
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Fedoryak OD, Searls Y, Smirnova IV, Burns DM, Stehno-Bittel L. Spontaneous Ca2+ oscillations in subcellular compartments of vascular smooth muscle cells rely on different Ca2+ pools. Cell Res 2005; 14:379-88. [PMID: 15538970 DOI: 10.1038/sj.cr.7290238] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Spontaneous Ca2+ oscillations in vascular smooth muscle cells have been modeled using a single Ca2+ pool. This report describes spontaneous Ca2+ oscillations dependent on two separate Ca2+ sources for the nuclear versus cytoplasmic compartments. Changes in free intracellular Ca2+ were monitored with ratiometric Ca2+- fluorophores using confocal microscopy. On average, spontaneous oscillations developed in 79% of rat aortic smooth muscle cells that were synchronous between the cytoplasm and nucleus. Reduction of extracellular Ca2+ (less than 1 microM)decreased the frequency and amplitude of the cytoplasmic oscillations with 48% of the oscillations asynchronous between the nuclear and cytoplasmic compartments. Similar results were obtained with the Ca2+ channel blockers, nimodipine and diltiazem. Arg-vasopressin (AVP) induced a rapid release of intracellular Ca2+ stores that was greater in the nuclear compartment (4.20 +/- 0.23 ratio units, n = 56) than cytoplasm (2.54 +/- 0.28) in cells that had spontaneously developed prior oscillations. Conversely, cells in the same conditions lacking oscillations had a greater AVP-induced Ca2+ transient in the cytoplasm (4.99 +/- 0.66, n = 17) than in the nucleus (2.67 +/- 0.29). Pre-treatment with Ca2+ channel blockers depressed the AVP responses in both compartments with the cytoplasmic Ca2+ most diminished. Depletion of internal Ca2+ stores prior to AVP exposure blunted the nuclear response, mimicking the response of cells that lacked prior oscillations. Spontaneous oscillating cells had a greater sarcoplasmic reticulum network than cells that did not oscillate. We propose that spontaneous nuclear oscillations rely on perinuclear sarcoplasmic reticulum stores, while the cytoplasmic oscillations rely on Ca2+ influx.
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Affiliation(s)
- Olesya D Fedoryak
- Department of Physical Therapy, University of Kansas Medical Center, Kansas City, KS 66160, USA
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37
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Curtis TM, Tumelty J, Dawicki J, Scholfield CN, McGeown JG. Identification and spatiotemporal characterization of spontaneous Ca2+ sparks and global Ca2+ oscillations in retinal arteriolar smooth muscle cells. Invest Ophthalmol Vis Sci 2005; 45:4409-14. [PMID: 15557449 PMCID: PMC2590679 DOI: 10.1167/iovs.04-0719] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To identify spontaneous Ca(2+) sparks and global Ca(2+) oscillations in microvascular smooth muscle (MVSM) cells within intact retinal arterioles and to characterize their spatiotemporal properties and physiological functions. METHODS Retinal arterioles were mechanically dispersed from freshly isolated rat retinas and loaded with Fluo-4, a Ca(2+)-sensitive dye. Changes in [Ca(2+)](i) were imaged in MVSM cells in situ by confocal scanning laser microscopy in x-y mode or line-scan mode. RESULTS The x-y scans revealed discretely localized, spontaneous Ca(2+) events resembling Ca(2+) sparks and more global and prolonged Ca(2+) transients, which sometimes led to cell contraction. In line scans, Ca(2+) sparks were similar to those previously described in other types of smooth muscle, with an amplitude (DeltaF/F(0)) of 0.81 +/- 0.04 (mean +/- SE), full duration at half maximum (FDHM) of 23.62 +/- 1.15 ms, full width at half maximum (FWHM) of 1.25 +/- 0.05 mum, and frequency of 0.56 +/- 0.06 seconds(-1). Approximately 35% of sparks had a prolonged tail (>80 ms), similar to the Ca(2+)"embers" described in skeletal muscle. Sparks often summated to generate global and prolonged Ca(2+) elevations on which Ca(2+) sparks were superimposed. These sparks occurred more frequently (2.86 +/- 025 seconds(-1)) and spread farther across the cell (FWHM = 1.67 +/- 0.08 microm), but were smaller (DeltaF/F(0) = 0.69 +/- 0.04). CONCLUSIONS Retinal arterioles generate Ca(2+) sparks with characteristics that vary during different phases of the spontaneous Ca(2+)-signaling cycle. Sparks summate to produce sustained Ca(2+) transients associated with contraction and thus may play an important excitatory role in initiating vessel constriction. This deserves further study, not least because Ca(2+) sparks appear to inhibit contraction in many other smooth muscle cells.
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Affiliation(s)
- Tim M Curtis
- Ophthalmic Research Centre, The Queen's University of Belfast, Institute of Clinical Sciences, The Royal Victoria Hospital, Belfast, Northern Ireland
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38
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Pan BX, Zhao GL, Huang XL, Zhao KS. Mobilization of intracellular calcium by peroxynitrite in arteriolar smooth muscle cells from rats. Redox Rep 2004; 9:49-55. [PMID: 15035827 DOI: 10.1179/135100004225003914] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The present study was designed to investigate the possible effects of peroxynitrite (ONOO(-)) on the intracellular calcium concentration ([Ca(2+)](i)) of mesenteric arteriolar smooth muscle cells (ASMCs), and to reveal the underlying mechanisms by using fluorescence imaging analysis. The results showed that ONOO(-) could exert a concentration- and time-dependent but also a dual effect on [Ca(2+)](i). Bolus administration with a low concentration of ONOO(-) (25 microM) decreased [Ca(2+)](i), whereas higher concentrations (50 or 100 microM) increased [Ca(2+)](i) persistently. Further experiments demonstrated that pretreatment of ASMCs with calcium-free medium completely abolished [Ca(2+)](i) increase by 100 microM ONOO(-). Additionally, nifedipine, an antagonist of selective L-type voltage-gated calcium channels (VGCCs), delayed the [Ca(2+)](i) response to ONOO(-), and ryanodine, an inhibitor of intracellular calcium release from the sarcoplasmic reticulum, effectively antagonized [Ca(2+)](i) increase during the late stage of ONOO(-) exposure. Furthermore, [Ca(2+)](i) alteration by ONOO(-) appeared to be intimately associated with the subsequent membrane potential changes. Although the mechanisms by which ONOO(-) alters [Ca(2+)](i) are complex, we conclude that a series of variables such as external calcium influx, activation of VGCCs, intracellular calcium release, and membrane potential changes are involved. The decrease of [Ca(2+)](i) in ASMCs by a low concentration of ONOO(-) may participate in the pathogenesis of low vasoreactivity in shock, and the increase of [Ca(2+)](i) by high concentrations of ONOO(-) may lead to calcium overload with cellular injury.
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Affiliation(s)
- Bing-Xing Pan
- Department of Pathophysiology, First Military Medical University, Guangzhou, People's Republic of China
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39
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Moffatt JD, Cocks TM. Pharmacologically distinct intracellular calcium pools regulate tonic and oscillatory responses in porcine thoracic duct. J Cardiovasc Pharmacol 2004; 43:83-92. [PMID: 14668572 DOI: 10.1097/00005344-200401000-00013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The present study investigated the mechanisms by which the thromboxane A2 mimetic U46619 can elicit phasic and tonic contractions in the pig thoracic duct, whereas other agonists like 5-hydroxytryptamine (5-HT) produce tonic contractions only. Tonic contractions in response to either agonist were abolished by the l-type voltage-operated calcium channel (VOCC) inhibitor nifedipine, the store-operated calcium channel inhibitor SKF 96365, the calcium-sensitive chloride channel (ClCa) inhibitor niflumic acid, and by removal of extracellular Cl-. Superimposed phasic responses to U46619 were abolished by only nifedipine. Inhibitors of K+ channels did not prevent phasic contractions to U46619. The IP3 receptor antagonist 2-APB attenuated tonic contractions only, whereas ryanodine and removal of extracellular Na+ selectively abolished phasic contractions to U46619. Therefore, selective initiation of phasic contractions by U46619 appears to depend on intracellular Ca2+ from a ryanodine-sensitive store that causes depolarization via Na+/Ca2+ exchange, whereas tonic contractions to U46619 and 5-HT are mediated primarily by release of IP3-mobilized intracellular Ca2+ that subsequently causes ClCa opening, membrane depolarization, and Ca2+ entry via l-type VOCC.
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Affiliation(s)
- James D Moffatt
- Department of Pharmacology, University of Melbourne, Parkville, Victoria, Australia.
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40
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Ay B, Prakash YS, Pabelick CM, Sieck GC. Store-operated Ca2+ entry in porcine airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2003; 286:L909-17. [PMID: 14617522 DOI: 10.1152/ajplung.00317.2003] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ca(2+) influx triggered by depletion of sarcoplasmic reticulum (SR) Ca(2+) stores [mediated via store-operated Ca(2+) channels (SOCC)] was characterized in enzymatically dissociated porcine airway smooth muscle (ASM) cells. When SR Ca(2+) was depleted by either 5 microM cyclopiazonic acid or 5 mM caffeine in the absence of extracellular Ca(2+), subsequent introduction of extracellular Ca(2+) further elevated [Ca(2+)](i). SOCC was insensitive to 1 microM nifedipine- or KCl-induced changes in membrane potential. However, preexposure of cells to 100 nM-1 mM La(3+) or Ni(2+) inhibited SOCC. Exposure to ACh increased Ca(2+) influx both in the presence and absence of a depleted SR. Inhibition of inositol 1,4,5-trisphosphate (IP)-induced SR Ca(2+) release by 20 microM xestospongin D inhibited SOCC, whereas ACh-induced IP(3) production by 5 microM U-73122 had no effect. Inhibition of Ca(2+) release through ryanodine receptors (RyR) by 100 microM ryanodine also prevented Ca(2+) influx via SOCC. Qualitatively similar characteristics of SOCC-mediated Ca(2+) influx were observed with cyclopiazonic acid- vs. caffeine-induced SR Ca(2+) depletion. These data demonstrate that a Ni(2+)/La(3+)-sensitive Ca(2+) influx via SOCC in porcine ASM cells involves SR Ca(2+) release through both IP(3) and RyR channels. Additional regulation of Ca(2+) influx by agonist may be related to a receptor-operated, noncapacitative mechanism.
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Affiliation(s)
- Binnaz Ay
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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41
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Brain KL, Cuprian AM, Williams DJ, Cunnane TC. The sources and sequestration of Ca(2+) contributing to neuroeffector Ca(2+) transients in the mouse vas deferens. J Physiol 2003; 553:627-35. [PMID: 14500773 PMCID: PMC2343581 DOI: 10.1113/jphysiol.2003.049734] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The detection of focal Ca(2+) transients (called neuroeffector Ca(2+) transients, or NCTs) in smooth muscle of the mouse isolated vas deferens has been used to detect the packeted release of ATP from nerve terminal varicosities acting at postjunctional P2X receptors. The present study investigates the sources and sequestration of Ca(2+) in NCTs. Smooth muscle cells in whole mouse deferens were loaded with the Ca(2+) indicator Oregon Green 488 BAPTA-1 AM and viewed with a confocal microscope. Ryanodine (10 microM) decreased the amplitude of NCTs by 45 +/- 6 %. Cyclopiazonic acid slowed the recovery of NCTs (from a time course of 200 +/- 10 ms to 800 +/- 100 ms). Caffeine (3 mM) induced spontaneous focal smooth muscle Ca(2+) transients (sparks). Neither of the T-type Ca(2+) channel blockers NiCl2 (50 microM) or mibefradil dihydrochloride (10 microM) affected the amplitude of excitatory junction potentials (2 +/- 5 % and -3 +/- 10 %) or NCTs (-20 +/- 36 % and 3 +/- 13 %). In about 20 % of cells, NCTs were associated with a local, subcellular twitch that remained in the presence of the alpha1-adrenoceptor antagonist prazosin (100 nM), showing that NCTs can initiate local contractions. Slow (5.8 +/- 0.4 microm s(-1)), spontaneous smooth muscle Ca(2+) waves were occasionally observed. Thus, Ca(2+) stores initially amplify and then sequester the Ca(2+) that enters through P2X receptors and there is no amplification by local voltage-gated Ca(2+) channels.
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Affiliation(s)
- Keith L Brain
- University Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
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42
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Bergner A, Sanderson MJ. Airway contractility and smooth muscle Ca(2+) signaling in lung slices from different mouse strains. J Appl Physiol (1985) 2003; 95:1325-32; discussion 1314. [PMID: 12777405 DOI: 10.1152/japplphysiol.00272.2003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To investigate the hypothesis that altered Ca2+ signaling in airway smooth muscle cells (SMCs) is responsible for airway hyperreactivity, we compared, with the use of confocal and phase-contrast microscopy, the airway contractility and Ca2+ changes in SMCs induced by acetylcholine (ACh) in lung slices from different mouse strains (A/J, Balb/C, and C3H/ HeJ). The airways from each mouse strain displayed a concentration-dependent contraction to ACh. The contractile response of the airways of the C3H/HeJ mice was found, in contrast to earlier studies, to be much greater and faster than that of A/J and Balb/C mice. This difference in airway reactivity can be, in part, attributable to halothane, a volatile anesthetic that was previously used during in vivo measurements of airway reactivity but found here to significantly alter the ACh contractile response of airways in lung slices. The ACh-induced Ca2+ response of the airway SMCs in all of the various mouse strains was also concentration dependent. The magnitude of the initial Ca2+ increase and the frequency of the subsequent Ca2+ oscillations induced by ACh increased with ACh concentration. However, no differences in the Ca2+ responses to ACh could be distinguished between the mouse strains. These results suggest that the mechanism responsible for airway hyperreactivity in different mouse strains resides with the Ca2+ sensitivity of the contractile apparatus of the SMCs rather than with the Ca2+ signaling itself.
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Affiliation(s)
- Albrecht Bergner
- Department of Physiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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43
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Fernandez SF, Huang MH, Davidson BA, Knight PR, Izzo JL. Modulation of angiotensin II responses in sympathetic neurons by cytosolic calcium. Hypertension 2003; 41:56-63. [PMID: 12511530 DOI: 10.1161/01.hyp.0000047513.75459.7e] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Both stimulatory and suppressive responses of the sympathetic nervous system to angiotensin II (AII) have been reported in intact animals. To elucidate possible cellular mechanisms, we studied AII-induced changes in cytosolic Ca2+ ([Ca2+]i) in primary cultures of rat stellate ganglion neurons. Two different patterns of [Ca2+]i responses to AII were observed: dose-dependent increases in [Ca2+]i in cells with intrinsically low baseline [Ca2+]i (n=64) and dose-dependent suppression of [Ca2+]i in neurons with intrinsically higher baseline [Ca2+]i (n=46). Individual neurons could express both response patterns to AII. In neurons with low basal [Ca2+]i, superfusion with Ca2+ ionophore (ionomycin) increased [Ca2+]i and reversed the initial AII-induced stimulatory pattern. L-type Ca2+ channel antagonism (nifedipine) in neurons with high baseline [Ca2+]i lowered [Ca2+]i and reversed the initial AII-induced suppressive response. Both stimulatory and suppressive responses were abolished by AT1 receptor antagonism (losartan). AII-induced stimulatory responses were blocked by IP3 receptor antagonism (2-APB) and by thapsigargin. AII-induced suppression of neuronal [Ca2+]i was blunted when Na-Ca exchange was impaired. We conclude that [Ca2+]i acts as a switch for AII-mediated stimulatory and suppressive responses in individual sympathetic neurons. AT1 receptor-mediated neuronal stimulation and suppression may allow local homeostatic adaptation to meet complex systemic needs.
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Affiliation(s)
- Stanley F Fernandez
- Department of Pharmacology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
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44
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Karkanis T, DeYoung L, Brock GB, Sims SM. Ca2+-activated Cl- channels in corpus cavernosum smooth muscle: a novel mechanism for control of penile erection. J Appl Physiol (1985) 2003; 94:301-13. [PMID: 12391071 DOI: 10.1152/japplphysiol.00660.2002] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Little is known of the excitatory mechanisms that contribute to the tonic contraction of the corpus cavernosum smooth muscle in the flaccid state. We used patch-clamp electrophysiology to investigate a previously unidentified inward current in freshly isolated rat and human corporal myocytes. Phenylephrine (PE) contracted cells and activated whole cell currents. Outward current was identified as large-conductance Ca(2+)-activated K(+) current. The inward current elicited by PE was dependent on the Cl(-) gradient and was inhibited by niflumic acid, indicative of a Ca(2+)-activated Cl(-) (Cl(Ca)) current. Furthermore, spontaneous transient outward and inward currents (STOCs and STICs, respectively) were identified in both rat and human corporal myocytes and derived from large-conductance Ca(2+)-activated K(+) and Cl(Ca) channel activity. STICs and STOCs were inhibited by PE and A-23187, and combined 8-bromoadenosine cAMP and 8-bromoadenosine cGMP decreased their frequency. When studied in vivo, chloride channel blockers transiently increased intracavernosal pressure and prolonged nerve-evoked erections. This report reveals for the first time Cl(Ca) current in rat and human corpus cavernosum smooth muscle cells and demonstrates its key functional role in the regulation of penile erection.
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Affiliation(s)
- Tom Karkanis
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada N6A 5C1
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45
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Bergner A, Sanderson MJ. ATP stimulates Ca2+ oscillations and contraction in airway smooth muscle cells of mouse lung slices. Am J Physiol Lung Cell Mol Physiol 2002; 283:L1271-9. [PMID: 12388370 DOI: 10.1152/ajplung.00139.2002] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In airway smooth muscle cells (SMCs) from mouse lung slices, > or =10 microM ATP induced Ca2+ oscillations that were accompanied by airway contraction. After approximately 1 min, the Ca2+ oscillations subsided and the airway relaxed. By contrast, > or =0.5 microM adenosine 5'-O-(3-thiotriphosphate) (nonhydrolyzable) induced Ca2+ oscillations in the SMCs and an associated airway contraction that persisted for >2 min. Adenosine 5'-O-(3-thiotriphosphate)-induced Ca2+ oscillations occurred in the absence of external Ca2+ but were abolished by the phospholipase C inhibitor U-73122 and the inositol 1,4,5-trisphosphate receptor inhibitor xestospongin. Adenosine, AMP, and alpha,beta-methylene ATP had no effect on airway caliber, and the magnitude of the contractile response induced by a variety of nucleotides could be ranked in the following order: ATP = UTP > ADP. These results suggest that the SMC response to ATP is impaired by ATP hydrolysis and mediated via P2Y(2) or P2Y(4) receptors, activating phospholipase C to release Ca2+ via the inositol 1,4,5-trisphosphate receptor. We conclude that ATP can serve as a spasmogen of airway SMCs and that Ca2+ oscillations in SMCs are required to sustain airway contraction.
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Affiliation(s)
- Albrecht Bergner
- Department of Physiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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46
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Gomez MF, Stevenson AS, Bonev AD, Hill-Eubanks DC, Nelson MT. Opposing actions of inositol 1,4,5-trisphosphate and ryanodine receptors on nuclear factor of activated T-cells regulation in smooth muscle. J Biol Chem 2002; 277:37756-64. [PMID: 12145283 DOI: 10.1074/jbc.m203596200] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The nuclear factor of activated T-cells (NFAT), originally identified in T-cells, has since been shown to play a role in mediating Ca(2+)-dependent gene transcription in diverse cell types outside of the immune system. We have previously shown that nuclear accumulation of NFATc3 is induced in ileal smooth muscle by platelet-derived growth factor in a manner that depends on Ca(2+) influx through L-type, voltage-dependent Ca(2+) channels. Here we show that NFATc3 is also the predominant NFAT isoform expressed in cerebral artery smooth muscle and is induced to accumulate in the nucleus by UTP and other G(q/11)-coupled receptor agonists. This induction is mediated by calcineurin and is dependent on sarcoplasmic reticulum Ca(2+) release through inositol 1,4,5-trisphosphate receptors and extracellular Ca(2+) influx through L-type, voltage-dependent Ca(2+) channels. Consistent with results obtained in ileal smooth muscle, depolarization-induced Ca(2+) influx fails to induce NFAT nuclear accumulation in cerebral arteries. We also provide evidence that Ca(2+) release by ryanodine receptors in the form of Ca(2+) sparks may exert an inhibitory influence on UTP-induced NFATc3 nuclear accumulation and further suggest that UTP may act, in part, by inhibiting Ca(2+) sparks. These results are consistent with a multifactorial regulation of NFAT nuclear accumulation in smooth muscle that is likely to involve several intracellular signaling pathways, including local effects of sarcoplasmic reticulum Ca(2+) release and effects attributable to global elevations in intracellular Ca(2+).
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Affiliation(s)
- Maria F Gomez
- Department of Pharmacology, University of Vermont, Burlington, Vermont 05405, USA
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47
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Tolić-Nørrelykke IM, Butler JP, Chen J, Wang N. Spatial and temporal traction response in human airway smooth muscle cells. Am J Physiol Cell Physiol 2002; 283:C1254-66. [PMID: 12225988 DOI: 10.1152/ajpcell.00169.2002] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Tractions that cells exert on their substrates are essential in cell spreading, migration, and contraction. These tractions can be determined by plating the cells on a flexible gel and measuring the deformation of the gel by using fluorescent beads embedded just below the surface of the gel. In this article we describe the image correlation method (ICM) optimized for determining the displacement field of the gel under a contracting cell. For the calculation of the traction field from the displacement field we use the recently developed method of Fourier transform traction cytometry (FTTC). The ICM and FTTC methods are applied to human airway smooth muscle cells during stimulation with the contractile agonist histamine or the relaxing agonist isoproterenol. The overall intensity of the cell contraction (the median traction magnitude, the energy transferred from the cell to the gel, and the net contractile moment) increased after activation with histamine, and decreased after treatment with isoproterenol. Cells exhibited regional differences in the time course of traction during the treatment. Both temporal evolution and magnitude of traction increase induced by histamine varied markedly among different cell protrusions, whereas the nuclear region showed the smallest response. These results suggest that intracellular mediators of cell adhesion and contraction respond to contractile stimuli with different rates and intensities in different regions of the cell.
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48
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Janssen LJ. Ionic mechanisms and Ca(2+) regulation in airway smooth muscle contraction: do the data contradict dogma? Am J Physiol Lung Cell Mol Physiol 2002; 282:L1161-78. [PMID: 12003770 DOI: 10.1152/ajplung.00452.2001] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In general, excitation-contraction coupling in muscle is dependent on membrane depolarization and hyperpolarization to regulate the opening of voltage-dependent Ca(2+) channels and, thereby, influence intracellular Ca(2+) concentration ([Ca(2+)](i)). Thus Ca(2+) channel blockers and K(+) channel openers are important tools in the arsenals against hypertension, stroke, and myocardial infarction, etc. Airway smooth muscle (ASM) also exhibits robust Ca(2+), K(+), and Cl(-) currents, and there are elaborate signaling pathways that regulate them. It is easy, then, to presume that these also play a central role in contraction/relaxation of ASM. However, several lines of evidence speak to the contrary. Also, too many researchers in the ASM field view the sarcoplasmic reticulum as being centrally located and displacing its contents uniformly throughout the cell, and they have focused almost exclusively on the initial single [Ca(2+)] spike evoked by excitatory agonists. Several recent studies have revealed complex spatial and temporal heterogeneity in [Ca(2+)](i), the significance of which is only just beginning to be appreciated. In this review, we will compare what is known about ion channels in ASM with what is believed to be their roles in ASM physiology. Also, we will examine some novel ionic mechanisms in the context of Ca(2+) handling and excitation-contraction coupling in ASM.
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Affiliation(s)
- Luke J Janssen
- Asthma Research Group, Firestone Institute for Respiratory Health, St. Joseph's Hospital, McMaster University, Hamilton, Ontario, Canada L8N 4A6.
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Stout MA, Raeymaekers L, De Smedt H, Casteels R. Characterization of Ca2+ release from heterogeneous Ca2+ stores in sarcoplasmic reticulum isolated from arterial and gastric smooth muscle. Can J Physiol Pharmacol 2002; 80:588-603. [PMID: 12117308 DOI: 10.1139/y02-083] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ca2+ transport was investigated in vesicles of sarcoplasmic reticulum subfractionated from bovine main pulmonary artery and porcine gastric antrum using digitonin binding and zonal density gradient centrifugation. Gradient fractions recovered at 15-33% sucrose were studied as the sarcoplasmic reticulum component using Fluo-3 fluorescence or 45Ca2+ Millipore filtration. Thapsigargin blocked active Ca2+ uptake and induced a slow Ca2+ release from actively loaded vesicles. Unidirectional 45Ca2+ efflux from passively loaded vesicles showed multicompartmental kinetics. The time course of an initial fast component could not be quantitatively measured with the sampling method. The slow release had a half-time of several minutes. Both components were inhibited by 20 microM ruthenium red and 10 mM Mg2+. Caffeine, inositol 1,4,5-trisphosphate, ATP, and diltiazem accelerated the slow component. A Ca2+ release component activated by ryanodine or cyclic adenosine diphosphate ribose was resolved with Fluo-3. Comparison of tissue responses showed that the fast Ca2+ release was significantly smaller and more sensitive to inhibition by Mg2+ and ruthenium red in arterial vesicles. They released more Ca2+ in response to inositol 1,4,5-trisphosphate and were more sensitive to activation by cyclic adenosine diphosphate ribose. Ryanodine and caffeine, in contrast, were more effective in gastric antrum. In each tissue, the fraction of the Ca2+ store released by sequential application of caffeine and inositol 1,4,5-trisphosphate depended on the order applied and was additive. The results indicate that sarcoplasmic reticulum purified from arterial and gastric smooth muscle represents vesicle subpopulations that retain functional Ca2+ channels that reflect tissue-specific pharmacological modulation. The relationship of these differences to physiological responses has not been determined.
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Bergner A, Sanderson MJ. Acetylcholine-induced calcium signaling and contraction of airway smooth muscle cells in lung slices. J Gen Physiol 2002; 119:187-98. [PMID: 11815668 PMCID: PMC2233801 DOI: 10.1085/jgp.119.2.187] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2001] [Revised: 01/09/2002] [Accepted: 01/11/2002] [Indexed: 11/20/2022] Open
Abstract
The Ca(2+) signaling and contractility of airway smooth muscle cells (SMCs) were investigated with confocal microscopy in murine lung slices (approximately 75-microm thick) that maintained the in situ organization of the airways and the contractility of the SMCs for at least 5 d. 10--500 nM acetylcholine (ACH) induced a contraction of the airway lumen and a transient increase in [Ca(2+)](i) in individual SMCs that subsequently declined to initiate multiple intracellular Ca(2+) oscillations. These Ca(2+) oscillations spread as Ca(2+) waves through the SMCs at approximately 48 microm/s. The magnitude of the airway contraction, the initial Ca(2+) transient, and the frequency of the subsequent Ca(2+) oscillations were all concentration-dependent. In a Ca(2+)-free solution, ACH induced a similar Ca(2+) response, except that the Ca(2+) oscillations ceased after 1--1.5 min. Incubation with thapsigargin, xestospongin, or ryanodine inhibited the ACH-induced Ca(2+) signaling. A comparison of airway contraction with the ACH-induced Ca(2+) response of the SMCs revealed that the onset of airway contraction correlated with the initial Ca(2+) transient, and that sustained airway contraction correlated with the occurrence of the Ca(2+) oscillations. Buffering intracellular Ca(2+) with BAPTA prohibited Ca(2+) signaling and airway contraction, indicating a Ca(2+)-dependent pathway. Cessation of the Ca(2+) oscillations, induced by ACH-esterase, halothane, or the absence of extracellular Ca(2+) resulted in a relaxation of the airway. The concentration dependence of the airway contraction matched the concentration dependence of the increased frequency of the Ca(2+) oscillations. These results indicate that Ca(2+) oscillations, induced by ACH in murine bronchial SMCs, are generated by Ca(2+) release from the SR involving IP(3)- and ryanodine receptors, and are required to maintain airway contraction.
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Affiliation(s)
- Albrecht Bergner
- Department of Physiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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