Bronchial inflammation induced PKCζ over-expression: involvement in mechanical properties of airway smooth muscle

2012 ◽  
Vol 90 (2) ◽  
pp. 261-269 ◽  
Author(s):  
Caroline Morin ◽  
Samuel Fortin ◽  
Eric Rousseau
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Airway Smooth Muscle ◽  
Regulatory Protein ◽  
Peptide Inhibitor ◽  
In Vivo Model ◽  
Bronchial Inflammation

Protein kinase C variants (PKCs) have been involved in the control of airway smooth muscle (ASM) tone, and abnormalities in PKC-dependent signaling have been associated with respiratory diseases such as asthma. In this study, the role of atypical PKCζ in airway hyperresponsiveness was investigated, using an in-vitro model of TNFα-treated human bronchi and an in vivo guinea pig model of chronic asthma. Our results demonstrated that PKCζ-specific inhibition produced a significant increase in isoproterenol sensitivity in TNFα-treated bronchi and ovalbumin (OVA)-sensitized guinea pig bronchi. The role of epoxy-eicosanoids, known to exert anti-inflammatory effects in lung, on PKCζ expression and activity in these models was evaluated. An enhanced PKCζ protein expression was delineated in TNFα-treated bronchi when compared with control (untreated) and epoxy-eicosanoid-treated bronchi. Measurements of Ca2+ sensitivity, performed in TNFα-treated bronchi, demonstrated that treatment with myristoylated (Myr) PKCζ peptide inhibitor resulted in significant reductions of pCa-induced tension. Epoxy-eicosanoid treatments had similar effects on Ca2+ sensitivity in TNFα-treated bronchi. In control and epoxy-eicosanoid-treated bronchi, the phosphorylated forms of p38MAPK and CPI-17 were significantly decreased compared with the TNFα-treated bronchi. An enhanced expression of PKCζ was ascertained in our in-vivo model of allergic asthma. Hence an increased Ca2+ sensitivity could be explained by the phosphorylation of p38-MAPK, which in turn leads to phosphorylation and activation of the CPI-17 regulatory protein. This process was reversed upon treatment with the Myr-PKCζ-peptide inhibitor. The present data provide relevant evidence regarding the role of PKCζ in human and rodent models of airways inflammation.

Tachyphylaxis to β-adrenoceptor agonists in guinea pig airway smooth muscle in vivo and in vitro

1977 ◽  
Vol 42 (3) ◽  
pp. 195-205 ◽  
Author(s):  
James S. Douglas ◽  
Alan J. Lewis ◽  
Pamela Ridgway ◽  
Charles Brink ◽  
Arend Bouhuys
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Airway Smooth Muscle ◽  
Adrenoceptor Agonists

scholarly journals Quercetin acutely relaxes airway smooth muscle and potentiates β-agonist-induced relaxation via dual phosphodiesterase inhibition of PLCβ and PDE4

2013 ◽  
Vol 305 (5) ◽  
pp. L396-L403 ◽  
Author(s):  
Elizabeth A. Townsend ◽  
Charles W. Emala
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Inositol Phosphate ◽  
Selective Inhibitor ◽  
In Vitro Assays ◽  
In Vivo Model ◽  
Chronic Obstructive ◽  
Airway Narrowing

Asthma is a disease of the airways with symptoms including exaggerated airway narrowing and airway inflammation. Early asthma therapies used methylxanthines to relieve symptoms, in part, by inhibiting cyclic nucleotide phosphodiesterases (PDEs), the enzyme responsible for degrading cAMP. The classification of tissue-specific PDE subtypes and the clinical introduction of PDE-selective inhibitors for chronic obstructive pulmonary disease (i.e., roflumilast) have reopened the possibility of using PDE inhibition in the treatment of asthma. Quercetin is a naturally derived PDE4-selective inhibitor found in fruits, vegetables, and tea. We hypothesized that quercetin relaxes airway smooth muscle via cAMP-mediated pathways and augments β-agonist relaxation. Tracheal rings from male A/J mice were mounted in myographs and contracted with acetylcholine (ACh). Addition of quercetin (100 nM-1 mM) acutely and concentration-dependently relaxed airway rings precontracted with ACh. In separate studies, pretreatment with quercetin (100 μM) prevented force generation upon exposure to ACh. In additional studies, quercetin (50 μM) significantly potentiated isoproterenol-induced relaxations. In in vitro assays, quercetin directly attenuated phospholipase C activity, decreased inositol phosphate synthesis, and decreased intracellular calcium responses to Gq-coupled agonists (histamine or bradykinin). Finally, nebulization of quercetin (100 μM) in an in vivo model of airway responsiveness significantly attenuated methacholine-induced increases in airway resistance. These novel data show that the natural PDE4-selective inhibitor quercetin may provide therapeutic relief of asthma symptoms and decrease reliance on short-acting β-agonists.

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.

scholarly journals Aging-associated changes in microRNA expression profile of internal anal sphincter smooth muscle: Role of microRNA-133a

2016 ◽  
Vol 311 (5) ◽  
pp. G964-G973 ◽  
Author(s):  
Jagmohan Singh ◽  
Ettickan Boopathi ◽  
Sankar Addya ◽  
Benjamin Phillips ◽  
Isidore Rigoutsos ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Anal Sphincter ◽  
Internal Anal Sphincter ◽  
Smooth Muscles ◽  
Smooth Muscle Contractility ◽  
Network Analyses ◽  
Rhoa Signaling

A comprehensive genomic and proteomic, computational, and physiological approach was employed to examine the (previously unexplored) role of microRNAs (miRNAs) as regulators of internal anal sphincter (IAS) smooth muscle contractile phenotype and basal tone. miRNA profiling, genome-wide expression, validation, and network analyses were employed to assess changes in mRNA and miRNA expression in IAS smooth muscles from young vs. aging rats. Multiple miRNAs, including rno-miR-1, rno-miR-340-5p, rno-miR-185, rno-miR-199a-3p, rno-miR-200c, rno-miR-200b, rno-miR-31, rno-miR-133a, and rno-miR-206, were found to be upregulated in aging IAS. qPCR confirmed the upregulated expression of these miRNAs and downregulation of multiple, predicted targets ( Eln, Col3a1, Col1a1, Zeb2, Myocd, Srf, Smad1, Smad2, Rhoa/Rock2, Fn1, Tagln v2, Klf4, and Acta2) involved in regulation of smooth muscle contractility. Subsequent studies demonstrated an aging-associated increase in the expression of miR-133a, corresponding decreases in RhoA, ROCK2, MYOCD, SRF, and SM22α protein expression, RhoA-signaling, and a decrease in basal and agonist [U-46619 (thromboxane A2analog)]-induced increase in the IAS tone. Moreover, in vitro transfection of miR-133a caused a dose-dependent increase of IAS tone in strips, which was reversed by anti-miR-133a. Last, in vivo perianal injection of anti-miR-133a reversed the loss of IAS tone associated with age. This work establishes the important regulatory effect of miRNA-133a on basal and agonist-stimulated IAS tone. Moreover, reversal of age-associated loss of tone via anti-miR delivery strongly implicates miR dysregulation as a causal factor in the aging-associated decrease in IAS tone and suggests that miR-133a is a feasible therapeutic target in aging-associated rectoanal incontinence.

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.

scholarly journals In vitro, in silico and in vivo study challenges the impact of bronchial thermoplasty on acute airway smooth muscle mass loss

2018 ◽  
Vol 51 (5) ◽  
pp. 1701680 ◽  
Author(s):  
Igor L. Chernyavsky ◽  
Richard J. Russell ◽  
Ruth M. Saunders ◽  
Gavin E. Morris ◽  
Rachid Berair ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Asthma Control ◽  
Muscle Mass ◽  
Airway Smooth Muscle ◽  
In Silico ◽  
Heat Distribution ◽  
Airway Wall ◽  
Epithelial Integrity

Bronchial thermoplasty is a treatment for asthma. It is currently unclear whether its histopathological impact is sufficiently explained by the proportion of airway wall that is exposed to temperatures necessary to affect cell survival.Airway smooth muscle and bronchial epithelial cells were exposed to media (37–70°C) for 10 s to mimic thermoplasty. In silico we developed a mathematical model of airway heat distribution post-thermoplasty. In vivo we determined airway smooth muscle mass and epithelial integrity pre- and post-thermoplasty in 14 patients with severe asthma.In vitro airway smooth muscle and epithelial cell number decreased significantly following the addition of media heated to ≥65°C. In silico simulations showed a heterogeneous heat distribution that was amplified in larger airways, with <10% of the airway wall heated to >60°C in airways with an inner radius of ∼4 mm. In vivo at 6 weeks post-thermoplasty, there was an improvement in asthma control (measured via Asthma Control Questionnaire-6; mean difference 0.7, 95% CI 0.1–1.3; p=0.03), airway smooth muscle mass decreased (absolute median reduction 5%, interquartile range (IQR) 0–10; p=0.03) and epithelial integrity increased (14%, IQR 6–29; p=0.007). Neither of the latter two outcomes was related to improved asthma control.Integrated in vitro and in silico modelling suggest that the reduction in airway smooth muscle post-thermoplasty cannot be fully explained by acute heating, and nor did this reduction confer a greater improvement in asthma control.

scholarly journals The Strain on Airway Smooth Muscle During a Deep Inspiration to Total Lung Capacity

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Ynuk Bossé
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Total Lung Capacity ◽  
In Vitro Studies ◽  
Deep Inspiration ◽  
Bronchodilator Effect ◽  
Lung Capacity ◽  
Residual Capacity

The deep inspiration (DI) maneuver entices a great deal of interest because of its ability to temporarily ease the flow of air into the lungs. This salutary effect of a DI is proposed to be mediated, at least partially, by momentarily increasing the operating length of airway smooth muscle (ASM). Concerningly, this premise is largely derived from a growing body of in vitro studies investigating the effect of stretching ASM by different magnitudes on its contractility. The relevance of these in vitro findings remains uncertain, as the real range of strains ASM undergoes in vivo during a DI is somewhat elusive. In order to understand the regulation of ASM contractility by a DI and to infer on its putative contribution to the bronchodilator effect of a DI, it is imperative that in vitro studies incorporate levels of strains that are physiologically relevant. This review summarizes the methods that may be used in vivo in humans to estimate the strain experienced by ASM during a DI from functional residual capacity (FRC) to total lung capacity (TLC). The strengths and limitations of each method, as well as the potential confounders, are also discussed. A rough estimated range of ASM strains is provided for the purpose of guiding future in vitro studies that aim at quantifying the regulatory effect of DI on ASM contractility. However, it is emphasized that, owing to the many limitations and confounders, more studies will be needed to reach conclusive statements.

Role of endothelial cells in regulating hemoglobin-induced changes in lymphatic pumping

1992 ◽  
Vol 263 (6) ◽  
pp. H1880-H1887 ◽  
Author(s):  
R. M. Elias ◽  
J. Eisenhoffer ◽  
M. G. Johnston
Keyword(s):  
Endothelial Cells ◽  
Smooth Muscle ◽  
Inhibitory Effect ◽  
Direct Inhibitory Effect ◽  
Induced Changes ◽  
Lymphatic Pumping ◽  
Pumping Activity

Studies with a sheep isolated duct preparation in vivo demonstrated that the route of administration of hemoglobin was important in demonstrating its inhibitory effect on lymphatic pumping. With autologous oxyhemoglobin administered intravenously (final plasma concentration 5 x 10(-5) M), pumping was not inhibited. However, the addition of oxyhemoglobin (5 x 10(-5) M) into the reservoir (lumen of the duct) resulted in > 95% inhibition of pumping. The extraluminal administration of oxyhemoglobin (10(-5) M) to bovine mesenteric lymphatics in vitro resulted in a 40% inhibition of pumping, whereas the introduction of oxyhemoglobin (10(-5) M) into the lumen of the vessels suppressed pumping 95%. In vessels mechanically denuded of endothelium, intraluminal oxyhemoglobin inhibited pumping 50%. These results suggested that oxyhemoglobin depressed pumping through an effect on both smooth muscle and endothelium. Once pumping was inhibited with oxyhemoglobin administration, stimulation of the duct with elevations in transmural pressure restored pumping activity when endothelial cells were present. However, in the absence of endothelium, pumping decreased with increases in distending pressures. We conclude that oxyhemoglobin has a direct inhibitory effect on lymphatic smooth muscle. The ability of oxyhemoglobin to alter the pressure range over which the lymph pump operates appears to be dependent on an intact endothelium.

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