Exogenous Irritant-Induced Airway Hyperreactivity and Inhibition of Soluble Guanylyl Cyclase

2008 ◽  
Vol 10 (2) ◽  
pp. 93-101 ◽  
Author(s):  
Martina Antošová ◽  
Anna Strapková ◽  
Tomáš Turčan

The majority of nitric oxide (NO) effects in the respiratory system are caused by stimulation of soluble guanylyl cyclase (sGC) with subsequent increase of cyclic guanosine monophosphate (cGMP) production. The importance of this mechanism of NO action in airway hyperreactivity (AHR) pathogenesis is unknown. Therefore, the aim of our experiment was to examine the changes of airway reactivity enhanced by toluene vapor exposure in the presence or inhibition of sGC activity in guinea pigs. Animals were treated with a nonspecific sGC inhibitor, methylene blue, in a dose of 50 or 100 mg/kg body weight, administered by intraperitoneal injection 30 min before or after exposure to toluene vapors. The toluene exposure lasted 2 hr in each of 3 consecutive days under in vivo conditions. Thereafter, the tracheal and lung tissue smooth muscle response to cumulative doses of mediators (histamine or acetylcholine) was recorded under in vitro conditions. The exposure to toluene vapors significantly increased the airway reactivity to both mediators in comparison with the healthy animal group. The administration of methylene blue decreased the amplitude of airway smooth muscle contraction in toluene-induced hyperreactivity. The decreases were dependent on the inhibitor doses, on a regimen of administration (before or after toluene inhalation), the level of the respiratory system (trachea, lung), and the bronchoconstrictor mediators. Our results suggest that the interaction between NO and sGC may be important for airway reactivity changes, but other mechanisms of NO action are important in AHR pathogenesis, too.

2006 ◽  
Vol 290 (1) ◽  
pp. L179-L184 ◽  
Author(s):  
Andreas Papapetropoulos ◽  
Davina C. M. Simoes ◽  
Georgia Xanthou ◽  
Charis Roussos ◽  
Christina Gratziou

Soluble guanylyl cyclase (sGC) is an enzyme highly expressed in the lung that generates cGMP contributing to airway smooth muscle relaxation. To determine whether the bronchoconstriction observed in asthma is accompanied by changes in sGC expression, we used a well-established murine model of allergic asthma. Histological and biochemical analyses confirmed the presence of inflammation in the lungs of mice sensitized and challenged with ovalbumin (OVA). Moreover, mice sensitized and challenged with OVA exhibited airway hyperreactivity to methacholine inhalation. Steady-state mRNA levels for all sGC subunits (α1, α2, and β1) were reduced in the lungs of mice with allergic asthma by 60–80%, as estimated by real-time PCR. These changes in mRNA were paralleled by changes at the protein level: α1, α2, and β1 expression was reduced by 50–80% as determined by Western blotting. Reduced α1 and β1 expression in bronchial smooth muscle cells was demonstrated by immunohistochemistry. To study if sGC inhibition mimics the airway hyperreactivity seen in asthma, we treated naïve mice with a selective sGC inhibitor. Indeed, in mice receiving ODQ the methacholine dose response was shifted to the left. We conclude that sGC expression is reduced in experimental asthma contributing to the observed airway hyperreactivity.


Author(s):  
Thomas J Pirtle ◽  
Richard A Satterlie

Abstract Typically, the marine mollusk, Clione limacina, exhibits a slow, hovering locomotor gait to maintain its position in the water column. However, the animal exhibits behaviorally relevant locomotor swim acceleration during escape response and feeding behavior. Both nitric oxide and serotonin mediate this behavioral swim acceleration. In this study, we examine the role that the second messenger, cGMP, plays in mediating nitric oxide and serotonin-induced swim acceleration. We observed that the application of an analog of cGMP or an activator of soluble guanylyl cyclase increased fictive locomotor speed recorded from Pd-7 interneurons of the animal’s locomotor central pattern generator. Moreover, inhibition of soluble guanylyl cyclase decreased fictive locomotor speed. These results suggest that basal levels of cGMP are important for slow swimming and that increased production of cGMP mediates swim acceleration in Clione. Because nitric oxide has its effect through cGMP signaling and because we show herein that cGMP produces cellular changes in Clione swim interneurons that are consistent with cellular changes produced by serotonin application, we hypothesize that both nitric oxide and serotonin function via a common signal transduction pathway that involves cGMP. Our results show that cGMP mediates nitric oxide-induced but not serotonin-induced swim acceleration in Clione.


2010 ◽  
Vol 298 (2) ◽  
pp. H562-H569 ◽  
Author(s):  
Qi Xi ◽  
Edward Umstot ◽  
Guiling Zhao ◽  
Damodaran Narayanan ◽  
Charles W. Leffler ◽  
...  

Glutamate is the principal cerebral excitatory neurotransmitter and dilates cerebral arterioles to match blood flow to neural activity. Arterial contractility is regulated by local and global Ca2+ signals that occur in smooth muscle cells, but modulation of these signals by glutamate is poorly understood. Here, using high-speed confocal imaging, we measured the Ca2+ signals that occur in arteriole smooth muscle cells of newborn piglet tangential brain slices, studied signal regulation by glutamate, and investigated the physiological function of heme oxygenase (HO) and carbon monoxide (CO) in these responses. Glutamate elevated Ca2+ spark frequency by ∼188% and reduced global intracellular Ca2+ concentration ([Ca2+]i) to ∼76% of control but did not alter Ca2+ wave frequency in brain arteriole smooth muscle cells. Isolation of cerebral arterioles from brain slices abolished glutamate-induced Ca2+ signal modulation. In slices treated with l-2-α-aminoadipic acid, a glial toxin, glutamate did not alter Ca2+ sparks or global [Ca2+]i but did activate Ca2+ waves. This shift in Ca2+ signal modulation by glutamate did not occur in slices treated with d-2-α-aminoadipic acid, an inactive isomer of l-2-α-aminoadipic acid. In the presence of chromium mesoporphyrin, a HO blocker, glutamate inhibited Ca2+ sparks and Ca2+ waves and did not alter global [Ca2+]i. In isolated arterioles, CORM-3 [tricarbonylchloro(glycinato)ruthenium(II)], a CO donor, activated Ca2+ sparks and reduced global [Ca2+]i. These effects were blocked by 1 H-(1,2,4)-oxadiazolo-(4,3-a)-quinoxalin-1-one, a soluble guanylyl cyclase inhibitor. Collectively, these data indicate that glutamate can modulate Ca2+ sparks, Ca2+ waves, and global [Ca2+]i in arteriole smooth muscle cells via mechanisms that require astrocytes and HO. These data also indicate that soluble guanylyl cyclase is involved in CO activation of Ca2+ sparks in arteriole smooth muscle cells.


2011 ◽  
Vol 89 (7) ◽  
pp. 467-476 ◽  
Author(s):  
Ji Seok Baik ◽  
Ju-Tae Sohn ◽  
Seong-Ho Ok ◽  
Jae-Gak Kim ◽  
Hui-Jin Sung ◽  
...  

Levobupivacaine is a long-acting local anesthetic that intrinsically produces vasoconstriction in isolated vessels. The goals of this study were to investigate the calcium-dependent mechanism underlying levobupivacaine-induced contraction of isolated rat aorta in vitro and to elucidate the pathway responsible for the endothelium-dependent attenuation of levobupivacaine-induced contraction. Isolated rat aortic rings were suspended to record isometric tension. Cumulative levobupivacaine concentration–response curves were generated in either the presence or absence of the antagonists verapamil, nifedipine, SKF-96365, 2-aminoethoxydiphenylborate, Gd3+, NW-nitro-l-arginine methyl ester (L-NAME), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), and methylene blue, either alone or in combination. Verapamil, nifedipine, SKF-96365, 2-aminoethoxydiphenylborate, low calcium concentrations, and calcium-free Krebs solution attenuated levobupivacaine-induced contraction. Gd3+ had no effect on levobupivacaine-induced contraction. Levobupivacaine increased intracellular calcium levels in vascular smooth muscle cells. L-NAME, ODQ, and methylene blue increased levobupivacaine-induced contraction in endothelium-intact aorta. SKF-96365 attenuated calcium-induced contraction in a previously calcium-free isotonic depolarizing solution containing 100 mmol/L KCl. Levobupivacaine-induced contraction of rat aortic smooth muscle is mediated primarily by calcium influx from the extracellular space mainly via voltage-operated calcium channels and, in part, by inositol 1,4,5-trisphosphate receptor-mediated release of calcium from the sarcoplasmic reticulum. The nitric oxide – cyclic guanosine monophosphate pathway is involved in the endothelium-dependent attenuation of levobupivacaine-induced contraction.


2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Andrew Holt ◽  
Danielle Martin ◽  
Patti Shaver ◽  
Shaquria Adderley ◽  
Joshua Stone ◽  
...  

Atherosclerotic lower extremity peripheral artery disease (PAD) is among the most prevalent, morbid and mortal of all cardiovascular disorders. Pathologic arterial smooth muscle (ASM) cell migration is a major component of atherogenic PAD and efforts aimed at attenuating its progression are clinically essential. Cyclic nucleotide signaling has long been studied for its growth-mitigating properties in the setting of PAD and other vascular growth disorders. In this study we hypothesized that the novel, heme-independent soluble guanylyl cyclase activator BAY 60-2770 (BAY) inhibits ASM cell migration through phosphorylation of the protein kinase G (PKG) target and actin-binding protein vasodilator-stimulated phosphoprotein (VASP). In a rat model of injury-induced arterial growth, BAY significantly reduced neointima formation and luminal narrowing compared to vehicle (Veh)-treated control arteries after 2 weeks. Using rat and human ASM cells BAY significantly attenuated cell migration, reduced G:F actin, and increased cyclic GMP content, PKG activity and phosphorylated VASP at Ser239 (pVASP.S239) compared to Veh controls. Using site-directed mutagenesis, both full-length VASP-overexpressing (wild type, WT) and VASP.S239 phosphorylation-resistant mutants showed significantly reduced cell migration compared to naïve controls, however, there was no effect on cell migration between either VASP transfected group in the presence of BAY. Interestingly, both VASP mutants showed significantly increased PKG activity compared to naïve cells, and in turn pharmacologic PKG blockade in the presence of BAY fully reversed the inhibitory effect of BAY alone on cell migration. These data suggest BAY has capacity to inhibit ASM cell migration through cyclic GMP/PKG/VASP signaling yet through mechanisms independent of pVASP.S239. Findings from this study implicate BAY via cyclic GMP/PKG/VASP as a potential pharmacotherapeutic agent against aberrant ASM growth disorders such as PAD.


2019 ◽  
Vol 393 (2) ◽  
pp. 287-302 ◽  
Author(s):  
Andreas Friebe ◽  
Peter Sandner ◽  
Achim Schmidtko

AbstractCyclic guanosine monophosphate (cGMP) is a unique second messenger molecule formed in different cell types and tissues. cGMP targets a variety of downstream effector molecules and, thus, elicits a very broad variety of cellular effects. Its production is triggered by stimulation of either soluble guanylyl cyclase (sGC) or particulate guanylyl cyclase (pGC); both enzymes exist in different isoforms. cGMP-induced effects are regulated by endogenous receptor ligands such as nitric oxide (NO) and natriuretic peptides (NPs). Depending on the distribution of sGC and pGC and the formation of ligands, this pathway regulates not only the cardiovascular system but also the kidney, lung, liver, and brain function; in addition, the cGMP pathway is involved in the pathogenesis of fibrosis, inflammation, or neurodegeneration and may also play a role in infectious diseases such as malaria. Moreover, new pharmacological approaches are being developed which target sGC- and pGC-dependent pathways for the treatment of various diseases. Therefore, it is of key interest to understand this pathway from scratch, beginning with the molecular basis of cGMP generation, the structure and function of both guanylyl cyclases and cGMP downstream targets; research efforts also focus on the subsequent signaling cascades, their potential crosstalk, and also the translational and, ultimately, the clinical implications of cGMP modulation. This review tries to summarize the contributions to the “9th International cGMP Conference on cGMP Generators, Effectors and Therapeutic Implications” held in Mainz in 2019. Presented data will be discussed and extended also in light of recent landmark findings and ongoing activities in the field of preclinical and clinical cGMP research.


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