Eosinophils, major basic protein, and polycationic peptides augment bovine airway myocyte Ca2+mobilization

1998 ◽  
Vol 274 (6) ◽  
pp. L997-L1005 ◽  
Author(s):  
Mark E. Wylam ◽  
Nesli Gungor ◽  
Richard W. Mitchell ◽  
Jason G. Umans
Keyword(s):  
Smooth Muscle ◽  
Basic Protein ◽  
Muscle Tone ◽  
Dependent Manner ◽  
Major Basic Protein ◽  
Human Eosinophil ◽  
Intracellular Ca ◽  
Airway Tone

Previous studies in vivo or in isolated airway preparations have suggested that eosinophil-derived polycationic proteins enhance airway smooth muscle tone in an epithelium-dependent manner. We assessed the direct effects of activated human eosinophil supernatant, major basic protein (MBP), and polycationic polypeptides on basal and agonist-stimulated intracellular Ca2+concentrations ([Ca2+]i) in cultured bovine tracheal smooth muscle (TSM) cells. A 1-h incubation of myocytes with activated eosinophil buffer resulted in a doubling of basal [Ca2+]iand increased responsivity to histamine compared with myocytes that were exposed to sham-activated eosinophil buffer. In addition, concentration-dependent acute transient increases and subsequent 1-h sustained elevations of basal [Ca2+]iwere observed immediately after addition of MBP and model polycationic proteins. Finally, both peak and plateau [Ca2+]iresponses to bradykinin addition were augmented significantly in cultured myocytes that had been exposed to low concentrations of MBP or model polycationic proteins but were inhibited at greater concentrations. This elevated [Ca2+]ito polycationic proteins was manifest in epithelium-denuded bovine TSM strips as concentration-dependent increased basal tone. We conclude that activated eosinophil supernatant, MBP, and other polycationic proteins have a direct effect on both basal and subsequent agonist-elicited Ca2+mobilization in cultured TSM cells; TSM strips in vitro demonstrated, respectively, augmented and diminished responses to the contractile agonist acetylcholine. It is possible that alteration in myocyte Ca2+mobilization induced by these substances may influence clinical states of altered airway tone, such as asthma.

Epithelial augmentation of trachealis contraction caused by major basic protein of eosinophils

1989 ◽  
Vol 66 (4) ◽  
pp. 1867-1873 ◽  
Author(s):  
J. D. Brofman ◽  
S. R. White ◽  
J. S. Blake ◽  
N. M. Munoz ◽  
G. J. Gleich ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Basic Protein ◽  
Tracheal Smooth Muscle ◽  
Active Tension ◽  
Major Basic Protein ◽  
Human Eosinophil ◽  
Control Segment ◽  
Eosinophil Granule

We studied the effect of epithelial removal and intraepithelial administration of human eosinophil granule major basic protein (MBP) on the contraction of underlying canine tracheal smooth muscle in 23 dogs in vivo. A dual in situ tracheal preparation was utilized that allowed sharp excision of epithelium. The response to intra-arterial acetylcholine (ACh) was augmented substantially in five dogs receiving 200 micrograms MBP by intraepithelial instillation. Active tension elicited by 10(-8) mol intra-arterial ACh was 34.0 +/- 2.2 g/cm before and 46.1 +/- 2.6 g/cm 30 min after MBP (P less than 0.002). There was no change in active tension in the control segment in the same dogs after intraepithelial instillation of vehicle only (34.7 +/- 3.2 vs. 34.4 +/- 2.3 g/cm; P = NS). Instillation of MBP directly into the subepithelial tracheal smooth muscle did not alter contraction. To assess whether this augmentation was caused by inhibition of an epithelial-derived relaxant factor, additional studies were performed in nine other dogs in which the epithelium was excised discretely from one of the two tracheal segments. No significant differences in contractile response to ACh or relaxation response to isoproterenol were observed at 2, 15, 30, or 60 min after epithelial excision. We demonstrate that intraepithelial administration of MBP augments the contraction of underlying canine tracheal smooth muscle elicited by ACh. This augmentation is a direct effect of MBP and does not require antagonism of epithelial inhibition.

scholarly journals Distribution of Major Basic Protein on Human Airway following In Vitro Eosinophil Incubation

2010 ◽  
Vol 2010 ◽  
pp. 1-13 ◽  
Author(s):  
Ailing Xue ◽  
John Wang ◽  
Gary C. Sieck ◽  
Mark E. Wylam
Keyword(s):  
Smooth Muscle ◽  
Airway Hyperresponsiveness ◽  
Basic Protein ◽  
Muscle Layer ◽  
Eosinophil Infiltration ◽  
Dependent Manner ◽  
Major Basic Protein ◽  
Human Eosinophil ◽  
Smooth Muscle Layer ◽  
Human Airway

Major basic protein (MBP) released from activated eosinophils may influence airway hyperresponsiveness (AHR) by either direct effects on airway myocytes or by an indirect effect. In this study, human bronchi, freshly isolated human eosinophils, or MBP purified from human eosinophil granules were incubated for studying eosinophil infiltration and MBP localization. Eosinophils immediately adhered to intact human airway as well as to cultured human airway myocytes and epithelium. Following incubation 18–24 h, eosinophils migrated into the airway media, including the smooth muscle layer, but had no specific recruitment to airway neurons. Eosinophils released significant amounts of MBP within the airway media, including areas comprising the smooth muscle layer. Most deposits of MBP were focally discrete and restricted by immunologic detection to a maximum volume of∼300 μm3about the eosinophil. Native MBP applied exogenously was immediately deposited on the surface of the airway, but required at least 1 h to become detected within the media of the airway wall. Tissue MBP infiltration and deposition increased in a time- and concentration-dependent manner. Taken together, these findings suggest that eosinophil-derived cationic proteins may alter airway hyperresponsiveness (AHR) in vivo by an effect that is not limited to the bronchial epithelium.

Inhibition of dihydropyridine-sensitive calcium entry in hypoxic relaxation of airway smooth muscle

1995 ◽  
Vol 268 (2) ◽  
pp. L201-L206 ◽  
Author(s):  
C. Vannier ◽  
T. L. Croxton ◽  
L. S. Farley ◽  
C. A. Hirshman
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Muscle Tone ◽  
Bay K 8644 ◽  
O2 Concentration ◽  
Voltage Dependent ◽  
Progressive Hypoxia ◽  
Carbamyl Choline

Hypoxia dilates airways in vivo and reduces active tension of airway smooth muscle in vitro. To determine whether hypoxia impairs Ca2+ entry through voltage-dependent channels (VDC), we tested the ability of dihydropyridines to modulate hypoxia-induced relaxation of KCl- and carbamyl choline (carbachol)-contracted porcine bronchi. Carbachol- or KCl-contracted bronchial rings were exposed to progressive hypoxia in the presence or absence of 1 microM BAY K 8644 (an L-type-channel agonist). In separate experiments, rings were contracted with carbachol or KCl, treated with nifedipine (a VDC antagonist), and finally exposed to hypoxia. BAY K 8644 prevented hypoxia-induced relaxation in KCl-contracted bronchi. Nifedipine (10(-5) M) totally relaxed KCl- contracted bronchi. Carbachol-contracted bronchi were only partially relaxed by nifedipine but were completely relaxed when the O2 concentration of the gas was reduced from 95 to 0%. These data indicate that hypoxia can reduce airway smooth muscle tone by limiting entry of Ca2+ through a dihydropyridine-sensitive pathway, but that other mechanisms also contribute to hypoxia-induced relaxation of carbachol-contracted bronchi.

Absence of nonadrenergic noncholinergic relaxation in the cat cervical trachea

1988 ◽  
Vol 65 (6) ◽  
pp. 2524-2530 ◽  
Author(s):  
H. Don ◽  
D. G. Baker ◽  
C. A. Richardson
Keyword(s):  
Smooth Muscle ◽  
Vagal Stimulation ◽  
Muscle Tone ◽  
Dynamic Compliance ◽  
Tracheal Mucosa ◽  
In Vivo Experiments ◽  
Lower Airways ◽  
Cervical Trachea

Published in vivo experiments have not supported in vitro reports of the presence of nonadrenergic noncholinergic (NANC) inhibitory pathways in the cat trachea. We therefore examined these pathways, measuring tension in an innervated tracheal segment, flow resistance in more distal airways, and dynamic compliance, in 10 anesthetized mechanically ventilated cats. Initially, cervical vagal stimulation evoked contraction followed by relaxation of smooth muscle of trachea and lower airways; sympathetic stimulation evoked relaxation only. After muscarinic blockade and restoration of smooth muscle tone with 5-hydroxytryptamine (5-HT) applied topically to the tracheal mucosa, vagal stimulation did not affect tracheal segment tension, whereas sympathetic-evoked relaxation was preserved. Similar results were found when tone was restored with intravenous 5-HT, with vagal stimulation also decreasing resistance and increasing compliance. We conclude that NANC pathways are present in lower airways but not in the cervical trachea of the cat. We hypothesize that parasympathetic constriction of cat airway smooth muscle can occur without simultaneous NANC activation, whereas NANC activity occurs only in tandem with parasympathetic stimulation.

SM22α inhibits lamellipodium formation and migration via Ras-Arp2/3 signaling in synthetic VSMCs

2016 ◽  
Vol 311 (5) ◽  
pp. C758-C767 ◽  
Author(s):  
Pin Lv ◽  
Fan Zhang ◽  
Ya-Juan Yin ◽  
Yu-Can Wang ◽  
Min Gao ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Lesion ◽  
Flavonoid Compound ◽  
Cell Cortex ◽  
Dependent Manner ◽  
Nucleotide Exchange ◽  
Migration Activity ◽  
And Migration

We previously demonstrated that smooth muscle (SM) 22α promotes the migration activity in contractile vascular smooth muscle cells (VSMCs). Based on the varied functions exhibited by SM22α in different VSMC phenotypes, we investigated the effect of SM22α on VSMC migration under pathological conditions. The results demonstrated that SM22α overexpression in synthetic VSMCs inhibited platelet-derived growth factor (PDGF)-BB-induced cell lamellipodium formation and migration, which was different from its action in contractile cells. The results indicated two distinct mechanisms underlying inhibition of lamellipodium formation by SM22α, increased actin dynamic stability and decreased Ras activity via interference with interactions between Ras and guanine nucleotide exchange factor. The former inhibited actin cytoskeleton rearrangement in the cell cortex, while the latter significantly disrupted actin nucleation activation of the Arp2/3 complex. Baicalin, a herb-derived flavonoid compound, inhibited VSMC migration via upregulation of SM22α expression in vitro and in vivo. These data suggest that SM22α regulates lamellipodium formation and cell migration in a phenotype-dependent manner in VSMCs, which may be a new therapeutic target for vascular lesion formation.

scholarly journals Lineage Tracing Reveals the Dynamic Contribution of Pericytes to the Blood Vessel Remodeling in Pulmonary Hypertension

2020 ◽  
Vol 40 (3) ◽  
pp. 766-782 ◽  
Author(s):  
Jennifer Bordenave ◽  
Ly Tu ◽  
Nihel Berrebeh ◽  
Raphaël Thuillet ◽  
Amélie Cumont ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Structural Changes ◽  
Chronic Hypoxia ◽  
Transforming Growth Factor ◽  
Primary Cultures ◽  
Lineage Tracing ◽  
In Vivo Model ◽  
Dependent Manner

Objective: Excessive accumulation of resident cells within the pulmonary vascular wall represents the hallmark feature of the remodeling occurring in pulmonary arterial hypertension (PAH). Furthermore, we have previously demonstrated that pulmonary arterioles are excessively covered by pericytes in PAH, but this process is not fully understood. The aim of our study was to investigate the dynamic contribution of pericytes in PAH vascular remodeling. Approach and Results: In this study, we performed in situ, in vivo, and in vitro experiments. We isolated primary cultures of human pericytes from controls and PAH lung specimens then performed functional studies (cell migration, proliferation, and differentiation). In addition, to follow up pericyte number and fate, a genetic fate-mapping approach was used with an NG2CreER;mT/mG transgenic mice in a model of pulmonary arteriole muscularization occurring during chronic hypoxia. We identified phenotypic and functional abnormalities of PAH pericytes in vitro, as they overexpress CXCR (C-X-C motif chemokine receptor)-7 and TGF (transforming growth factor)-βRII and, thereby, display a higher capacity to migrate, proliferate, and differentiate into smooth muscle-like cells than controls. In an in vivo model of chronic hypoxia, we found an early increase in pericyte number in a CXCL (C-X-C motif chemokine ligand)-12-dependent manner whereas later, from day 7, activation of the canonical TGF-β signaling pathway induces pericytes to differentiate into smooth muscle-like cells. Conclusions: Our findings reveal a pivotal role of pulmonary pericytes in PAH and identify CXCR-7 and TGF-βRII as 2 intrinsic abnormalities in these resident progenitor vascular cells that foster the onset and maintenance of PAH structural changes in blood lung vessels.

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.

Effects of Triazoles on Smooth Muscle Tone and Immunologically Released Bronchoconstrictive Mediators in Vitro and in Vivo

2009 ◽  
Vol 55 (5) ◽  
pp. 418-421
Author(s):  
Rolf G. G. Andersson ◽  
Nils Grundström ◽  
Susan Hedman ◽  
Lars Sörenby ◽  
Jarl E. S. Wikberg
Keyword(s):  
Smooth Muscle ◽  
Muscle Tone ◽  
Smooth Muscle Tone

Role of Ca2+ entry in the modulation of airway tone by hypoxia

1993 ◽  
Vol 264 (3) ◽  
pp. L284-L289 ◽  
Author(s):  
L. B. Fernandes ◽  
K. Stuart-Smith ◽  
T. L. Croxton ◽  
C. A. Hirshman
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Soluble Guanylate Cyclase ◽  
Muscle Tone ◽  
Maintenance Phase ◽  
Dependent Manner ◽  
Cellular Mechanisms ◽  
Concentration Dependent Manner ◽  
Initiation Phase ◽  
Airway Tone

To evaluate the cellular mechanisms involved in hypoxic relaxation of airway smooth muscle, we investigated the effects of hypoxia on the behavior of third- and fourth-order porcine bronchial rings contracted with either carbachol or KCl. In one series of experiments, hypoxia (95% N2-5% CO2) was imposed and rings were then exposed to increasing concentrations of carbachol or KCl. In separate experiments, rings were first contracted with carbachol (10(-6) M) or KCl (40 mM) and were then exposed to solutions bubbled with decreasing concentrations of O2. The CO2 concentration was maintained constant at 5% in all experiments. The initial magnitude of KCl-induced but not carbachol-induced contractions was profoundly reduced by 95% N2-5% CO2. The sensitivity of the airway to carbachol was unchanged. In rings precontracted with either carbachol or KCl, hypoxia caused similar losses of airway smooth muscle tone in a reversible and concentration-dependent manner. The effects of hypoxia were independent of the presence of an intact epithelium and were not inhibited by the cyclooxygenase inhibitor indomethacin (5 microM), the soluble guanylate cyclase inhibitor methylene blue (50 microM), or the beta-adrenoceptor antagonist propranolol (1 microM). The impairment by hypoxia of the initiation phase of KCl-induced contractions and of the maintenance phase of both KCl- and carbachol-induced contractions, but not the initiation phase of carbachol-induced contractions, suggests that changes in O2 tension modulate airway tone by altering the entry of extracellular calcium into the airway smooth muscle.

Altered functional coupling of coronary K+ channels in diabetic dyslipidemic pigs is prevented by exercise

2003 ◽  
Vol 95 (3) ◽  
pp. 1179-1193 ◽  
Author(s):  
E. A. Mokelke ◽  
Q. Hu ◽  
M. Song ◽  
L. Toro ◽  
H. K. Reddy ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Ionic Currents ◽  
Functional Coupling ◽  
High Fat ◽  
Diabetic Dyslipidemia ◽  
Compensatory Response ◽  
Chronic Hyperglycemia ◽  
Intracellular Ca

Chronic hyperglycemia and hypercholesterolemia have been shown to alter ionic currents in vascular smooth muscle. We tested the hypothesis that the combined effect of hyperglycemia and hyperlipidemia (diabetic dyslipidemia) would increase the Ca2+-sensitive K+ (KCa) current as a compensatory response to an increase in intracellular Ca2+ concentration. We also hypothesized that exercise training would prevent this elevation in KCa current. Miniature Yucatan swine were randomly assigned to five groups: control, standard pig chow (C, n = 6); hyperlipidemic, high-fat pig chow (H, n = 5); diabetic, standard pig chow (D, n = 7); diabetic, high-fat pig chow (“diabetic dyslipidemic,” DD, n = 12); and exercise-trained DD (DDX, n = 9). High-fat chow consisted of standard minipig chow supplemented with cholesterol (2%) and coconut oil. Increased coronary vasoconstriction assessed in vivo and in vitro in DD was prevented by exercise. Patch-clamp experiments performed on right coronary artery smooth muscle cells resulted in greater K+ current densities in the H, D, and DD groups vs. the DDX group between -10 and 40 mV. In fura 2-loaded cells, current activated by caffeine-induced Ca2+ release was greater in H, D, and DD compared with C and DDX ( P < 0.05), whereas intracellular Ca2+ concentration was not different across groups. Finally, there were no differences in the KCa or Kv channel protein content between groups. These data indicate that hyperglycemia, hyperlipidemia, and diabetic dyslipidemia lead to elevated whole cell K+ current and increased functional coupling of KCa and Ca2+ release. Endurance exercise prevented increased coupling of Ca2+ release to KCa channel activation in diabetic dyslipidemia.

Sign in / Sign up

Export Citation Format

Share Document