Role of STIM1/Orai1-mediated store-operated Ca2+ entry in airway smooth muscle cell proliferation

2011 ◽  
Vol 110 (5) ◽  
pp. 1256-1263 ◽  
Author(s):  
Jin-jing Zou ◽  
Ya-dong Gao ◽  
Shuang Geng ◽  
Jiong Yang

Hyperplasia of airway smooth muscle cells (ASMCs) is a characteristic change of chronic asthma patients. However, the underlying mechanisms that trigger this process are not yet completely understood. Store-operated Ca2+ (SOC) entry (SOCE) occurs in response to the intracellular sarcoplasma reticulum (SR)/endoplasmic reticulum (ER) Ca2+ store depletion. SOCE plays an important role in regulating Ca2+ signaling and cellular responses of ASMCs. Stromal interaction molecule (STIM)1 has been proposed as an ER/SR Ca2+ sensor and translocates to the ER underneath the plasma membrane upon depletion of the ER Ca2+ store, where it interacts with Orai1, the molecular component of SOC channels, and brings about SOCE. STIM1 and Orai1 have been proved to mediate SOCE of ASMCs. In this study, we investigated whether STIM1/Orai1-mediated SOCE is involved in rat ASMC proliferation. We found that SOCE was upregulated during ASMC proliferation accompanied by a mild increase of STIM1 and a significant increase of Orai1 mRNA expression, whereas the proliferation of ASMCs was partially inhibited by the SOC channel blockers SKF-96365, NiCl2, and BTP-2. Suppressing the mRNA expression of STIM1 or Orai1 with specific short hairpin RNA resulted in the attenuation of SOCE and ASMC proliferation. Moreover, after knockdown of STIM1 or Orai1, the SOC channel blocker SKF-96365 had no inhibitory effect on the proliferation of ASMCs anymore. These results suggested that STIM1/Orai1-mediated SOCE is involved in ASMC proliferation.

2009 ◽  
Vol 297 (2) ◽  
pp. L326-L339 ◽  
Author(s):  
P. Seidel ◽  
I. Merfort ◽  
J. M. Hughes ◽  
B. G. G. Oliver ◽  
M. Tamm ◽  
...  

The antipsoriatic dimethylfumarate (DMF) has been anecdotically reported to reduce asthma symptoms and to improve quality of life of asthma patients. DMF decreases the expression of proinflammatory mediators by inhibiting the transcription factor NF-κB and might therefore be of interest for the therapy of inflammatory lung diseases. In this study, we determined the effect of DMF on platelet-derived growth factor (PDGF)-BB- and TNFα-induced asthma-relevant cytokines and NF-κB activation by primary human asthmatic and nonasthmatic airway smooth muscle cells (ASMC). Confluent nonasthmatic and asthmatic ASMC were incubated with DMF (0.1–100 μM) and/or dexamethasone (0.0001–0.1 μM), NF-κB p65 siRNA (100 nM), the NF-κB inhibitor helenalin (1 μM) before stimulation with PDGF-BB or TNFα (10 ng/ml). Cytokine release was measured by ELISA. NF-κB, mitogen and stress-activated kinase (MSK-1), and CREB activation was determined by immunoblotting and EMSA. TNFα-induced eotaxin, RANTES, and IL-6 as well as PDGF-BB-induced IL-6 expression was inhibited by DMF and by dexamethasone from asthmatic and nonasthmatic ASMC, but the combination of both drugs showed no glucocorticoid sparing effect in either of the two groups. NF-κB p65 siRNA and/or the NF-κB inhibitor helenalin reduced PDGF-BB- and TNFα-induced cytokine expression, suggesting the involvement of NF-κB signaling. DMF inhibited TNFα-induced NF-κB p65 phosphorylation, NF-κB nuclear entry, and NF-κB-DNA complex formation, whereas PDGF-BB appeared not to activate NF-κB within 60 min. Both stimuli induced the phosphorylation of MSK-1, NF-κB p65 at Ser276, and CREB, and all were inhibited by DMF. These data suggest that DMF downregulates cytokine secretion not only by inhibiting NF-κB but a wider range of NF-κB-linked signaling proteins, which may explain its potential beneficial effect in asthma.


1989 ◽  
Vol 256 (2) ◽  
pp. C329-C335 ◽  
Author(s):  
R. A. Panettieri ◽  
R. K. Murray ◽  
L. R. DePalo ◽  
P. A. Yadvish ◽  
M. I. Kotlikoff

We report the development of a nontransformed line of human airway smooth muscle cells retaining smooth muscle-specific contractile protein expression and physiological responsiveness to agonists implicated in inflammatory airway diseases. Specific responses to histamine, leukotrienes, bradykinin, platelet-activating factor, substance P, and thromboxane analogues are demonstrated as well as functional coupling to beta-adrenergic receptors. The cell line was characterized using indirect immunofluorescence, as well as electrophoretic separation and immunoblot analysis of smooth muscle-specific actin. Functional responses were assessed by measurements of cytosolic calcium and stimulation of adenosine 3',5'-cyclic monophosphate production. The cells retain their responsiveness over many population doublings and should be a useful model to examine specific receptor-effector mechanisms, as well as the effects of neurohumoral agents on the regulation of airway smooth muscle growth and differentiation.


2004 ◽  
Vol 287 (3) ◽  
pp. C643-C654 ◽  
Author(s):  
Marina Puig-de-Morales ◽  
Emil Millet ◽  
Ben Fabry ◽  
Daniel Navajas ◽  
Ning Wang ◽  
...  

We probed elastic and loss moduli in the adherent human airway smooth muscle cell through a variety of receptor systems, each serving as a different molecular window on cytoskeletal dynamics. Coated magnetic microbeads were attached to the cell surface via coating-receptor binding. A panel of bead coatings was investigated: a peptide containing the sequence RGD, vitronectin, urokinase, activating antibody against β1-integrin, nonactivating antibody against β1-integrin, blocking antibody against β1-integrin, antibody against β1-integrin, and acetylated low-density lipoprotein. An oscillatory mechanical torque was applied to the bead, and resulting lateral displacements were measured at baseline, after actin disruption by cytochalasin D, or after contractile activation by histamine. As expected, mechanical moduli depended strongly on bead type and bead coating, differing at the extremes by as much as two orders of magnitude. In every case, however, elastic and loss moduli increased with frequency f as a weak power law, f  x−1. Moreover, with few exceptions, data could be scaled such that elastic and frictional responses depended solely on the power law exponent x. Taken together, these data suggest that power law behavior represents a generic feature of underlying protein-protein dynamics.


1995 ◽  
Vol 268 (6) ◽  
pp. L1047-L1051 ◽  
Author(s):  
K. Maruno ◽  
A. Absood ◽  
S. I. Said

Airway smooth muscle (ASM) cell proliferation contributes to increased airway resistance in bronchial asthma. We have examined the modulation of ASM proliferation by vasoactive intestinal peptide (VIP), a cotransmitter of airway relaxation. Human ASM cells were grown in culture as a monolayer. VIP (1.0 nM-1.0 microM) inhibited proliferation in a dose-dependent manner by up to 82% on day 2, but the related peptide glucagon had no effect. Histamine (100 nM-100 microM) increased cell counts by 66%, but in the presence of VIP, cell counts and [3H]thymidine incorporation were reduced by up to 55%. Adenosine 3',5'-cyclic monophosphate (cAMP)-promoting agents, including 3-isobutyl-1-methylxanthine, forskolin, and 8-bromo-adenosine 3',5'-cyclic monophosphate, alone and especially combined with VIP, reduced cell counts and [3H]thymidine incorporation, in correlation with cAMP levels. KT-5720 (1.0 nM-1.0 microM), a selective inhibitor of cAMP-dependent protein kinase A (PKA), abolished the inhibitory effect of VIP. The results show that VIP selectively and potently inhibits human ASM cell growth and multiplication, and nullifies the mitogenic effect of histamine, by a PKA-mediated mechanism. A deficiency of VIP may lead to ASM hyperplasia due to unopposed stimulation by endogenous mitogens.


1994 ◽  
Vol 267 (2) ◽  
pp. L106-L112 ◽  
Author(s):  
T. L. Croxton ◽  
C. Fleming ◽  
C. A. Hirshman

Voltage-dependent and receptor-operated Ca2+ entry mechanisms have been demonstrated in airway smooth muscle, but their relative importance for maintenance of contraction is unknown. Blockade of voltage-dependent Ca2+ channels (VDC) has produced inconsistent relaxation. We postulated regional variations in Ca2+ handling by airway smooth muscle cells and compared the efficacy of dihydropyridine VDC blockers in tracheas and bronchi. Porcine tracheal smooth muscle strips and bronchial rings were mounted in tissue baths filled with physiological solutions and isometric tension was measured. Tissues were precontracted with carbachol or KCl, and relaxation dose-response curves to nifedipine, Mn2+, or Cd2+ were obtained. Relaxation responses to nifedipine were significantly different in carbachol-contracted tracheas and bronchi. Whereas carbachol-contracted tracheal muscle completely relaxed with 10(-6) M nifedipine, bronchial smooth muscle relaxed < 50%. In contrast, KCl-contracted bronchial muscle was completely relaxed by nifedipine. The nonspecific Ca2+ channel blockers Mn2+ and Cd2+ produced similar relaxation responses in each tissue. Thus VDC are the predominant mechanism for Ca2+ entry in porcine tracheal smooth muscle, but a dihydropyridine-insensitive pathway is functionally important in carbachol-contracted porcine bronchi. Regional variation may account for apparent inconsistencies between previous studies.


2006 ◽  
Vol 291 (5) ◽  
pp. C957-C965 ◽  
Author(s):  
Vasanthi Govindaraju ◽  
Marie-Claire Michoud ◽  
Mustafa Al-Chalabi ◽  
Pasquale Ferraro ◽  
William S. Powell ◽  
...  

In patients with cystic fibrosis (CF) and asthma, elevated levels of interleukin-8 (IL-8) are found in the airways. IL-8 is a CXC chemokine that is a chemoattractant for neutrophils through CXCR1 and CXCR2 G protein-coupled receptors. We hypothesized that IL-8 acts directly on airway smooth muscle cells (ASMC) in a way that may contribute to the enhanced airway responsiveness and airway remodeling observed in CF and asthma. The aim of this study was to determine whether human ASMC (HASMC) express functional IL-8 receptors (CXCR1 and CXCR2) linked to cell contraction and migration. Experiments were conducted on cells harvested from human lung specimens. Real-time PCR and fluorescence-activated cell sorting analysis showed that HASMC expressed mRNA and protein for both CXCR1 and CXCR2. Intracellular Ca2+ concentration ([Ca2+]i) increased from 115 to 170 nM in response to IL-8 (100 nM) and decreased after inhibition of phospholipase C (PLC) with U-73122. On blocking the receptors with specific neutralizing antibodies, changes in [Ca2+]i were abrogated. IL-8 also contracted the HASMC, decreasing the length of cells by 15%, and induced a 2.5-fold increase in migration. These results indicate that HASMC constitutively express functional CXCR1 and CXCR2 that mediate IL-8-triggered Ca2+ release, contraction, and migration. These data suggest a potential role for IL-8 in causing abnormal airway structure and function in asthma and CF.


2002 ◽  
Vol 282 (4) ◽  
pp. L847-L853 ◽  
Author(s):  
Paul E. Moore ◽  
Trudi L. Church ◽  
David D. Chism ◽  
Reynold A. Panettieri ◽  
Stephanie A. Shore

Human airway smooth muscle (HASM) cells express interleukin (IL)-13 and IL-4 receptors and respond to these cytokines with signal transducer and activator of transcription-6 and extracellular signal-regulated kinase (ERK) activation. The purpose of this study was to determine whether IL-13 and/or IL-4 influence eotaxin release in HASM cells and whether the ERK mitogen-activated protein (MAP) kinase pathway is involved in these events. Eotaxin release into HASM cell supernatants was assayed by ELISA, and eotaxin mRNA expression was determined by Northern blot analysis. Pretreatment with either IL-13 or IL-4 resulted in a concentration- and time-dependent release of eotaxin, although IL-4 was more effective. Eotaxin release was approximately twice baseline after treatment with 50 ng/ml IL-13 or IL-4 ( P < 0.001). IL-13 and IL-4 also acted synergistically with tumor necrosis factor (TNF)-α to induce eotaxin release: TNF-α alone (10 ng/ml for 24 h) resulted in an approximately fourfold increase in eotaxin release, whereas TNF-α in combination with IL-13 or IL-4 resulted in 10- or 20-fold increases ( P < 0.05). Similar results were obtained for eotaxin mRNA expression. Pretreatment with either U-0126 (10 μM) or PD-98059 (30 μM), both inhibitors of MAP/ERK kinase, the enzyme upstream of ERK, inhibited IL-13- or IL-4-induced eotaxin release ( P < 0.05). U-0126 also inhibited IL-13, and TNF-α induced mRNA expression. Our results indicate that IL-13 and IL-4 cause eotaxin release in HASM cells through a mechanism that, in part, involves ERK activation and suggest that the smooth muscle may be an important source of chemokines leading to eosinophil recruitment in asthma.


2013 ◽  
Vol 304 (9) ◽  
pp. C813-C820 ◽  
Author(s):  
Paul M. Vanhoutte

The presence of a healthy epithelium can moderate the contraction of the underlying airway smooth muscle. This is, in part, because epithelial cells generate inhibitory messages, whether diffusible substances, electrophysiological signals, or both. The epithelium-dependent inhibitory effect can be tonic (basal), synergistic, or evoked. Rather than a unique epithelium-derived relaxing factor (EpDRF), several known endogenous bronchoactive mediators, including nitric oxide and prostaglandin E2, contribute. The early concept that EpDRF diffuses all the way through the subepithelial layers to directly relax the airway smooth muscle appears unlikely. It is more plausible that the epithelial cells release true messenger molecules, which alter the production of endogenous substances (nitric oxide and/or metabolites of arachidonic acid) by the subepithelial layers. These substances then diffuse to the airway smooth muscle cells, conveying epithelium dependency.


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