Adrenomedullin insufficiency increases allergen-induced airway hyperresponsiveness in mice

2007 ◽  
Vol 102 (6) ◽  
pp. 2361-2368 ◽  
Author(s):  
Hiroshi Yamamoto ◽  
Takahide Nagase ◽  
Takayuki Shindo ◽  
Shinji Teramoto ◽  
Tomoko Aoki-Nagase ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Airway Hyperresponsiveness ◽  
Airway Responsiveness ◽  
Mutant Mice ◽  
Wild Type ◽  
T Helper 1 ◽  
Littermate Control

Adrenomedullin (ADM), a newly identified vasodilating peptide, is reported to be expressed in lungs and have a bronchodilating effect. We hypothesized whether ADM could be involved in the pathogenesis of bronchial asthma. We examined the role of ADM in airway responsiveness using heterozygous ADM-deficient mice ( AM+/−) and their littermate control ( AM+/+). Here, we show that airway responsiveness is enhanced in ADM mutant mice after sensitization and challenge with ovalbumin (OVA). The immunoreactive ADM level in the lung tissue after methacholine challenge was significantly greater in the wild-type mice than that in the mutant. However, the impairment of ADM gene function did not affect immunoglobulins (OVA-specific IgE and IgG1), T helper 1 and 2 cytokines, and leukotrenes. Thus the conventional mechanism of allergen-induced airway responsiveness is not relevant to this model. Furthermore, morphometric analysis revealed that eosinophilia and airway hypersecretion were similarly found in both the OVA-treated ADM mutant mice and the OVA-treated wild-type mice. On the other hand, the area of the airway smooth muscle layer of the OVA-treated mutant mice was significantly greater than that of the OVA-treated wild-type mice. These results suggest that ADM gene disruption may be associated with airway smooth muscle hyperplasia as well as enhanced airway hyperresponsiveness. ADM mutant mice might provide novel insights to study the pathophysiological role of ADM in vivo.

Mechanisms of airway smooth muscle relaxation during maturation

2005 ◽  
Vol 83 (10) ◽  
pp. 833-840 ◽  
Author(s):  
Lu Wang ◽  
Thomas M Murphy ◽  
Pasquale Chitano
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Airway Hyperresponsiveness ◽  
Muscle Relaxation ◽  
Electrical Field Stimulation ◽  
Airway Responsiveness ◽  
Smooth Muscle Relaxation ◽  
Asthma Prevalence ◽  
Spontaneous Relaxation

Greater airway responsiveness in healthy juveniles is considered a factor in the higher asthma prevalence at a young age compared with adults. We have developed a guinea pig maturational model that utilizes tracheal strips from 1-week-, 3-week-, and 3-month-old guinea pigs to study the role of airway smooth muscle (ASM) in juvenile airway hyperresponsiveness. Because a reduced ability of ASM to spontaneously relax may contribute to airway hyperresponsiveness by maintaining bronchospasm and thus high airway resistance, we have employed this model to study ASM spontaneous relaxation during electrical field stimulation (EFS). Since relaxation during EFS had been neither described nor quantified during maturation, we developed new indices that allowed an appropriate comparison of the relaxing response from strips of different age animals. Using these indices we found that, whereas strips from adult animals relax to a level of tension similar to that found in the absence of stimulation, this ability to spontaneously relax is essentially absent in trachealis from infant animals. These results confirmed that maturation of ASM relaxation may play a role in juvenile airway hyperresponsiveness and that our maturational model is suitable to study the mechanisms regulating spontaneous relaxation in physiological conditions. We investigated the role of prostanoids in ASM relaxation and showed that cyclooxygenase inhibition increases relaxation in infant ASM to levels similar to adults. These results suggest that prostanoids regulate the ability of ASM to spontaneously relax, i.e., they reduce relaxation. We have produced preliminary data suggesting a maturational change in the level of prostanoids. Moreover, the possible action of acetylcholinesterase on maturation of ASM relaxation is discussed here on the basis of a preliminary study. We suggest that impairment of ASM relaxation likely contributes to increased airway responsiveness.Key words: acetylcholinesterase, airway responsiveness, asthma, ontogenesis, prostanoids.

Ozone-induced airway hyperresponsiveness: roles of ROCK isoforms

2015 ◽  
Vol 309 (12) ◽  
pp. L1394-L1397 ◽  
Author(s):  
James A. Lambert ◽  
Weifeng Song
Keyword(s):  
Smooth Muscle ◽  
Muscle Contraction ◽  
Airway Smooth Muscle ◽  
Airway Hyperresponsiveness ◽  
Rho Kinase ◽  
Smooth Muscle Contraction ◽  
Wild Type ◽  
Epithelial Injury ◽  
Robust Evidence

Acute ozone (O3) inhalation has been shown to cause airway and pulmonary epithelial injury with accompanying inflammation responses. Robust evidence exists that O3 induces airway hyperresponsiveness (AHR) in humans and in animal models. Several pathways exist that culminate in airway smooth muscle contraction, but the mechanism(s) by which O3 elicits AHR are unclear. Here, we review the recent report by Kasahara et al. (Kasahara DI, Mathews JA, Park CY, Cho Y, Hunt G, Wurmbrand AP, Liao JK, Shore SA. Am J Physiol Lung Cell Mol Physiol 309: L736–L746, 2015.) describing the role of two Rho kinase (ROCK) isoforms in O3-induced AHR utilizing a murine haploinsufficiency model. Compared with wild-type (WT) mice, the authors report that ROCK1+/− and ROCK2+/− mice exhibited significantly reduced AHR following acute exposure to O3. Additionally, WT mice treated with fasudil, an FDA-approved ROCK1/2 inhibitor, recapitulated reduction in AHR as seen in ROCK haplotypes. It was suggested that, although the two ROCK isoforms are both induced by Rho, they have different mechanisms by which they mediate O3-induced AHR: ROCK1 via hyaluronan signaling vs. ROCK2 acting downstream of inflammation at the level of airway smooth muscle contraction. These observations provide an important framework to develop novel ROCK-targeting therapies for acute O3-induced AHR.

Heparan sulfate side chains have a critical role in the inhibitory effects of perlecan on vascular smooth muscle cell response to arterial injury

2014 ◽  
Vol 307 (3) ◽  
pp. H337-H345 ◽  
Author(s):  
Lara Gotha ◽  
Sang Yup Lim ◽  
Azriel B. Osherov ◽  
Rafael Wolff ◽  
Beiping Qiang ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Critical Role ◽  
Arterial Injury ◽  
Side Chains ◽  
Wild Type ◽  
Injury Response ◽  
Migratory Response

Perlecan is a proteoglycan composed of a 470-kDa core protein linked to three heparan sulfate (HS) glycosaminoglycan chains. The intact proteoglycan inhibits the smooth muscle cell (SMC) response to vascular injury. Hspg2Δ3/Δ3 (MΔ3/Δ3) mice produce a mutant perlecan lacking the HS side chains. The objective of this study was to determine differences between these two types of perlecan in modifying SMC activities to the arterial injury response, in order to define the specific role of the HS side chains. In vitro proliferative and migratory activities were compared in SMC isolated from MΔ3/Δ3 and wild-type mice. Proliferation of MΔ3/Δ3 SMC was 1.5× greater than in wild type ( P < 0.001), increased by addition of growth factors, and showed a 42% greater migratory response than wild-type cells to PDGF-BB ( P < 0.001). In MΔ3/Δ3 SMC adhesion to fibronectin, and collagen types I and IV was significantly greater than wild type. Addition of DRL-12582, an inducer of perlecan expression, decreased proliferation and migratory response to PDGF-BB stimulation in wild-type SMC compared with MΔ3/Δ3. In an in vivo carotid artery wire injury model, the medial thickness, medial area/lumen ratio, and macrophage infiltration were significantly increased in the MΔ3/Δ3 mice, indicating a prominent role of the HS side chain in limiting vascular injury response. Mutant perlecan that lacks HS side chains had a marked reduction in the inhibition of in vitro SMC function and the in vivo arterial response to injury, indicating the critical role of HS side chains in perlecan function in the vessel wall.

Hyperoxia-induced airway hyperresponsiveness and remodeling in immature rats

1992 ◽  
Vol 262 (3) ◽  
pp. L263-L269 ◽  
Author(s):  
M. B. Hershenson ◽  
S. Aghili ◽  
N. Punjabi ◽  
C. Hernandez ◽  
D. W. Ray ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Airway Hyperresponsiveness ◽  
Muscle Layer ◽  
Airway Responsiveness ◽  
Wall Thickening ◽  
Small Airways ◽  
Smooth Muscle Layer ◽  
Hyperoxic Exposure ◽  
Immature Rats

We exposed 21-day-old rats to either normoxia or hyperoxia (greater than 95% O2) for 8 days and assessed in vivo airway responsiveness to aerosolized and intravenous methacholine (MCh) and airway architecture. Airway responsiveness was determined using a plethysmographic method. Hyperoxia increased airway cholinergic responsiveness, as reflected in a decreased mean ED200 (concentration of MCh required to increase respiratory system resistance by 100%) for both aerosolized MCh [air exposed, 5.94 +/- 2.50 vs. O2 exposed, 0.29 +/- 3.34 (SD) mg/ml, P = 0.0013, unpaired t test] and intravenous MCh (air, 1.40 x 10(-8) vs. O2, 2.45 x 10(-10) mol/kg, P = 0.0002). Airway morphometry was studied in a separate cohort of animals. After fixation by distension with Formalin at 25 cmH2O pressure, each airway cross section was photographed, and airway circumference, epithelial area, and smooth muscle layer area were determined by means of contour tracing using a digitizing pad and microcomputer. For the small airways (circumference less than 1,000 microns), hyperoxia increased both mean epithelial thickness (air, 4.88 +/- 0.53; O2, 8.64 +/- 0.90 microns) and mean smooth muscle layer thickness (air, 2.69 +/- 0.11; O2, 4.79 +/- 0.56 microns; P less than 0.0001 for each). O2 had similar effects on the larger (1,000-3,000 microns) central airways (P less than 0.0001 for both layers). We conclude that chronic hyperoxic exposure induces both airway hyperresponsiveness and airway wall thickening in immature rats.

Airway smooth muscle tone increases airway responsiveness in healthy young adults

2017 ◽  
Vol 312 (3) ◽  
pp. L348-L357 ◽  
Author(s):  
Morgan Gazzola ◽  
Katherine Lortie ◽  
Cyndi Henry ◽  
Samuel Mailhot-Larouche ◽  
David G. Chapman ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Muscle Tone ◽  
Airway Responsiveness ◽  
High Dose ◽  
Forced Oscillation Technique ◽  
Single High Dose ◽  
Healthy Humans

Force adaptation, a process whereby sustained spasmogenic activation (viz., tone) of airway smooth muscle (ASM) increases its contractile capacity, has been reported in isolated ASM tissues in vitro, as well as in mice in vivo. The objective of the present study was to assess the effect of tone on airway responsiveness in humans. Ten healthy volunteers underwent methacholine challenge on two occasions. One challenge consisted of six serial doses of saline followed by a single high dose of methacholine. The other consisted of six low doses of methacholine 5 min apart followed by a higher dose. The cumulative dose was identical for both challenges. After both methacholine challenges, subjects took a deep inspiration (DI) to total lung capacity as another way to probe ASM mechanics. Responses to methacholine and the DI were measured using a multifrequency forced oscillation technique. Compared with a single high dose, the challenge preceded by tone led to an elevated response measured by respiratory system resistance (Rrs) and reactance at 5 Hz. However, there was no difference in the increase in Rrs at 19 Hz, suggesting a predominant effect on smaller airways. Increased tone also reduced the efficacy of DI, measured by an attenuated maximal dilation during the DI and an increased renarrowing post-DI. We conclude that ASM tone increases small airway responsiveness to inhaled methacholine and reduces the effectiveness of DI in healthy humans. This suggests that force adaptation may contribute to airway hyperresponsiveness and the reduced bronchodilatory effect of DI in asthma.

scholarly journals ROCK insufficiency attenuates ozone-induced airway hyperresponsiveness in mice

2015 ◽  
Vol 309 (7) ◽  
pp. L736-L746 ◽  
Author(s):  
David I. Kasahara ◽  
Joel A. Mathews ◽  
Chan Y. Park ◽  
Youngji Cho ◽  
Gabrielle Hunt ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Muscle Contraction ◽  
Airway Smooth Muscle ◽  
Airway Hyperresponsiveness ◽  
Matrix Protein ◽  
Pulmonary Inflammation ◽  
Inflammatory Cells ◽  
Smooth Muscle Contraction ◽  
Airway Smooth Muscle Cells ◽  
Wild Type

Ozone causes airway hyperresponsiveness (AHR) and pulmonary inflammation. Rho kinase (ROCK) is a key regulator of smooth muscle cell contraction and inflammatory cell migration. To determine the contribution of the two ROCK isoforms ROCK1 and ROCK2 to ozone-induced AHR, we exposed wild-type, ROCK1+/−, and ROCK2+/− mice to air or ozone (2 ppm for 3 h) and evaluated mice 24 h later. ROCK1 or ROCK2 haploinsufficiency did not affect airway responsiveness in air-exposed mice but significantly reduced ozone-induced AHR, with a greater reduction in ROCK2+/− mice despite increased bronchoalveolar lavage (BAL) inflammatory cells in ROCK2+/− mice. Compared with wild-type mice, ozone-induced increases in BAL hyaluronan, a matrix protein implicated in ozone-induced AHR, were lower in ROCK1+/− but not ROCK2+/− mice. Ozone-induced increases in other inflammatory moieties reported to contribute to ozone-induced AHR (IL-17A, osteopontin, TNFα) were not different in wild-type vs. ROCK1+/− or ROCK2+/− mice. We also observed a dose-dependent reduction in ozone-induced AHR after treatment with the ROCK1/ROCK2 inhibitor fasudil, even though fasudil was administered after induction of inflammation. Ozone increased pulmonary expression of ROCK2 but not ROCK1 or RhoA. A ROCK2 inhibitor, SR3677, reduced contractile forces in primary human airway smooth muscle cells, confirming a role for ROCK2 in airway smooth muscle contraction. Our results demonstrate that ozone-induced AHR requires ROCK. Whereas ROCK1-dependent changes in hyaluronan may contribute to ROCK1's role in O3-induced AHR, the role of ROCK2 is downstream of inflammation, likely at the level of airway smooth muscle contraction.

Airway smooth muscle responsiveness from dogs with airway hyperresponsiveness after O3 inhalation

1988 ◽  
Vol 65 (1) ◽  
pp. 57-64 ◽  
Author(s):  
G. L. Jones ◽  
P. M. O'Byrne ◽  
M. Pashley ◽  
R. Serio ◽  
J. Jury ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Potassium Chloride ◽  
Airway Smooth Muscle ◽  
Airway Hyperresponsiveness ◽  
Electrical Field Stimulation ◽  
Field Stimulation ◽  
Electrical Field ◽  
Trachealis Muscle

Airway hyperresponsiveness occurs after inhalation of O3 in dogs. The purpose of this study was to examine the responsiveness of trachealis smooth muscle in vitro to electrical field stimulation, exogenous acetylcholine, and potassium chloride from dogs with airway hyperresponsiveness after inhaled O3 in vivo and to compare this with the responsiveness of trachealis muscle from control dogs. In addition, excitatory junction potentials were measured with the use of single and double sucrose gap techniques in both groups of dogs to determine whether inhaled O3 affects the release of acetylcholine from parasympathetic nerves in trachealis muscle. Airway hyperresponsiveness developed in all dogs after inhaled O3 (3 ppm for 30 min). The acetylcholine provocative concentration decreased from 4.11 mg/ml before O3 inhalation to 0.66 mg/ml after O3 (P less than 0.0001). The acetylcholine provocative concentration increased slightly after control inhalation of dry room air. Airway smooth muscle showed increased responses to both electrical field stimulation and exogenous acetylcholine but not to potassium chloride in preparations from dogs with airway hyperresponsiveness in vivo. The increased response to electrical field stimulation was not associated with a change in excitatory junctional potentials. These results suggest that a postjunctional alteration in trachealis muscle function occurs after inhaled O3 in dogs, which may account for airway hyperresponsiveness after O3 in vivo.

scholarly journals Molecular Mechanisms for the Mechanical Modulation of Airway Responsiveness

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Wenwu Zhang ◽  
Susan J. Gunst
Keyword(s):  
Extracellular Matrix ◽  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Actin Polymerization ◽  
Molecular Mechanisms ◽  
Airway Responsiveness ◽  
Small Gtpase ◽  
Cortical Actin

The smooth muscle of the airways is exposed to continuously changing mechanical forces during normal breathing. The mechanical oscillations that occur during breathing have profound effects on airway tone and airway responsiveness both in experimental animals and humans in vivo and in isolated airway tissues in vitro. Experimental evidence suggests that alterations in the contractile and mechanical properties of airway smooth muscle tissues caused by mechanical perturbations result from adaptive changes in the organization of the cytoskeletal architecture of the smooth muscle cell. The cytoskeleton is a dynamic structure that undergoes rapid reorganization in response to external mechanical and pharmacologic stimuli. Contractile stimulation initiates the assembly of cytoskeletal/extracellular matrix adhesion complex proteins into large macromolecular signaling complexes (adhesomes) that undergo activation to mediate the polymerization and reorganization of a submembranous network of actin filaments at the cortex of the cell. Cortical actin polymerization is catalyzed by Neuronal-Wiskott–Aldrich syndrome protein (N-WASP) and the Arp2/3 complex, which are activated by pathways regulated by paxillin and the small GTPase, cdc42. These processes create a strong and rigid cytoskeletal framework that may serve to strengthen the membrane for the transmission of force generated by the contractile apparatus to the extracellular matrix, and to enable the adaptation of smooth muscle cells to mechanical stresses. This model for the regulation of airway smooth muscle function can provide novel perspectives to explain the normal physiologic behavior of the airways and pathophysiologic properties of the airways in asthma.

The effects of repeated allergen challenge on airway smooth muscle structural and molecular remodeling in a rat model of allergic asthma

2009 ◽  
Vol 297 (4) ◽  
pp. L698-L705 ◽  
Author(s):  
Isabelle Labonté ◽  
Muhannad Hassan ◽  
Paul-André Risse ◽  
Kimitake Tsuchiya ◽  
Michel Laviolette ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Ex Vivo ◽  
Mrna Level ◽  
Allergen Challenge ◽  
Airway Responsiveness ◽  
Brown Norway ◽  
Contractile Phenotype ◽  
The Relationship

The effects of remodeling of airway smooth muscle (SM) by hyperplasia on airway SM contractility in vivo are poorly explored. The aim of this study was to investigate the relationship between allergen-induced airway SM hyperplasia and its contractile phenotype. Brown Norway rats were sensitized with ovalbumin (OVA) or saline on day 0 and then either OVA-challenged once on day 14 and killed 24 h later or OVA-challenged 3 times (on days 14, 19, and 24) and killed 2 or 7 days later. Changes in SM mass, expression of total myosin, SM myosin heavy chain fast isoform (SM-B) and myosin light chain kinase (MLCK), tracheal contractions ex vivo, and airway responsiveness to methacholine (MCh) in vivo were assessed. One day after a single OVA challenge, the number of SM cells positive for PCNA was greater than for control animals, whereas the SM mass, contractile phenotype, and tracheal contractility were unchanged. Two days after three challenges, SM mass and PCNA immunoreactive cells were increased (3- and 10-fold, respectively; P < 0.05), but airway responsiveness to MCh was unaffected. Lower expression in total myosin, SM-B, and MLCK was observed at the mRNA level ( P < 0.05), and total myosin and MLCK expression were lower at the protein level ( P < 0.05) after normalization for SM mass. Normalized tracheal SM force generation was also significantly lower 2 days after repeated challenges ( P < 0.05). Seven days after repeated challenges, features of remodeling were restored toward control levels. Allergen-induced hyperplasia of SM cells was associated with a loss of contractile phenotype, which was offset by the increase in mass.

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