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LIMK2 is required for membrane cytoskeleton reorganization of contracting airway smooth muscle. J Genet Genomics 2021; 48:452-462. [PMID: 34353741 DOI: 10.1016/j.jgg.2021.04.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 04/14/2021] [Accepted: 04/26/2021] [Indexed: 11/23/2022]
Abstract
Airway smooth muscle (ASM) has developed a mechanical adaption mechanism by which it transduces force and responds to environmental forces, which is essential for periodic breathing. Cytoskeletal reorganization has been implicated in this process, but the regulatory mechanism remains to be determined. We here observe that ASM abundantly expresses cytoskeleton regulators Limk1 and Limk2, and their expression levels are further upregulated in chronic obstructive pulmonary disease (COPD) animals. By establishing mouse lines with deletions of Limk1 or Limk2, we analyse the length-sensitive contraction, F/G-actin dynamics, and F-actin pool of mutant ASM cells. As LIMK1 phosphorylation does not respond to the contractile stimulation, LIMK1-deficient ASM develops normal maximal force, while LIMK2 or LIMK1/LIMK2 deficient ASMs show approximately 30% inhibition. LIMK2 deletion causes a significant decrease in cofilin phosphorylation along with a reduced F/G-actin ratio. As LIMK2 functions independently of cross-bridge movement, this observation indicates that LIMK2 is necessary for F-actin dynamics and hence force transduction. Moreover, LIMK2-deficient ASMs display abolishes stretching-induced suppression of 5-hydroxytryptamine (5-HT) but not acetylcholine-evoks force, which is due to the differential contraction mechanisms adopted by the agonists. We propose that LIMK2-mediated cofilin phosphorylation is required for membrane cytoskeleton reorganization that is necessary for ASM mechanical adaption including the 5-HT-evoked length-sensitive effect.
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Zhao L, Liang YT, Tian DB, Zhang RG, Huang J, Zhu YX, Zhou WL, Zhang YL. Regulation of smooth muscle contractility by the epithelium in rat tracheas: role of prostaglandin E 2 induced by the neurotransmitter acetylcholine. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:313. [PMID: 33708940 PMCID: PMC7944331 DOI: 10.21037/atm-20-5500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Previous studies have suggested the involvement of epithelium in modulating the contractility of neighboring smooth muscle cells. However, the mechanism underlying epithelium-derived relaxation in airways remains largely unclear. This study aimed to investigate the mechanism underlying epithelium-dependent smooth muscle relaxation mediated by neurotransmitters. Methods The contractile tension of Sprague-Dawley (SD) rat tracheal rings were measured using a mechanical recording system. Intracellular Ca2+ level was measured using a Ca2+ fluorescent probe Fluo-3 AM, and the fluorescence signal was recorded by a laser scanning confocal imaging system. The prostaglandin E2 (PGE2) content was measured using an enzyme-linked immunosorbent assay kit. Results We observed that the neurotransmitter acetylcholine (ACh) restrained the electric field stimulation (EFS)-induced contraction in the intact but not epithelium-denuded rat tracheal rings. After inhibiting the muscarinic ACh receptor (mAChR) or cyclooxygenase (COX), a critical enzyme in prostaglandin synthesis, the relaxant effect of ACh was attenuated. Exogenous PGE2 showed a similar inhibitory effect on the EFS-evoked contraction of tracheal rings. Moreover, ACh triggered phospholipase C (PLC)-coupled Ca2+ release from intracellular Ca2+ stores and stimulated COX-dependent PGE2 production in primary cultured rat tracheal epithelial cells. Conclusions Collectively, this study demonstrated that ACh induced rat tracheal smooth muscle relaxation by promoting PGE2 release from tracheal epithelium, which might provide valuable insights into the cross-talk among neurons, epithelial cells and neighboring smooth muscle cells in airways.
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Affiliation(s)
- Lei Zhao
- Department of Respiration, Qingyuan People's Hospital, the Sixth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China.,School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China.,School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yu-Ting Liang
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Dong-Bo Tian
- Department of Respiration, Qingyuan People's Hospital, the Sixth Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China.,School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China
| | - Rui-Gang Zhang
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China.,Department of Physiology, Basic Medical School, Guangdong Medical University, Zhanjiang, China
| | - Jiehong Huang
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yun-Xin Zhu
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Wen-Liang Zhou
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yi-Lin Zhang
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
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Regulation of Airway Smooth Muscle Contraction in Health and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1124:381-422. [PMID: 31183836 DOI: 10.1007/978-981-13-5895-1_16] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Airway smooth muscle (ASM) extends from the trachea throughout the bronchial tree to the terminal bronchioles. In utero, spontaneous phasic contraction of fetal ASM is critical for normal lung development by regulating intraluminal fluid movement, ASM differentiation, and release of key growth factors. In contrast, phasic contraction appears to be absent in the adult lung, and regulation of tonic contraction and airflow is under neuronal and humoral control. Accumulating evidence suggests that changes in ASM responsiveness contribute to the pathophysiology of lung diseases with lifelong health impacts.Functional assessments of fetal and adult ASM and airways have defined pharmacological responses and signaling pathways that drive airway contraction and relaxation. Studies using precision-cut lung slices, in which contraction of intrapulmonary airways and ASM calcium signaling can be assessed simultaneously in situ, have been particularly informative. These combined approaches have defined the relative importance of calcium entry into ASM and calcium release from intracellular stores as drivers of spontaneous phasic contraction in utero and excitation-contraction coupling.Increased contractility of ASM in asthma contributes to airway hyperresponsiveness. Studies using animal models and human ASM and airways have characterized inflammatory and other mechanisms underlying increased reactivity to contractile agonists and reduced bronchodilator efficacy of β2-adrenoceptor agonists in severe diseases. Novel bronchodilators and the application of bronchial thermoplasty to ablate increased ASM within asthmatic airways have the potential to overcome limitations of current therapies. These approaches may directly limit excessive airway contraction to improve outcomes for difficult-to-control asthma and other chronic lung diseases.
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Welschoff J, Matthey M, Wenzel D. RGD peptides induce relaxation of pulmonary arteries and airways
via
β3‐integrins. FASEB J 2014; 28:2281-92. [DOI: 10.1096/fj.13-246348] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Rodríguez-Ramos F, González-Andrade M, Navarrete A. Gnaphaliin A and B relax smooth muscle of guinea-pig trachea and rat aorta via phosphodiesterase inhibition. ACTA ACUST UNITED AC 2011; 63:926-35. [PMID: 21635258 DOI: 10.1111/j.2042-7158.2011.01275.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To explore the relaxant mechanism of action of gnaphaliin A and gnaphaliin B in guinea-pig trachea and rat aorta, and to investigate the theoretical and experimental phosphodiesterase (PDE) inhibitory activity of these flavones. METHODS The relaxant effect and the inhibition of calcium chloride induced contractions of both flavones were evaluated on guinea-pig trachea and rat aorta rings. The PDE inhibitory activity was evaluated using a cyclic nucleotide PDE colorimetric assay kit with cAMP and cGMP as substrates. The docking analysis was carried out with AutoDock4 software and X-ray structure of PDE type 5. The activity of both gnaphaliins was compared with the activity of sildenafil, rolipram, aminophylline, IBMX and enoximone. KEY FINDINGS Gnaphaliin A and B were more actives as relaxants on rat aorta than guinea-pig trachea. They were less potent in the relaxation of guinea-pig trachea and rat aorta than sildenafil, but they were equal or more potent than the other PDE inhibitors tested. The relaxant effect of these flavones was potentiated by nitroprusside and forskolin, and blocked by 1H-[1,2,4]-oxadiazolo[4,3-a]quinoxalin-1-one but not by 2',5'-dideoxyadenosine in guinea-pig trachea. L-NAME did not modify the relaxant effect of gnaphaliins. Gnaphaliins were more potent as PDE inhibitors when cGMP was used as substrate. Docking analysis revealed that gnaphaiins bind to the same binding site of sildenafil at PDE type 5. CONCLUSIONS The results suggest that the main relaxant mechanism of action of gnaphaliin A and B is inhibition of PDEs with a preference to inhibit the degradation of cGMP. The docking study suggested that these flavones bind with high specificity to the same binding site of sildenafil at PDE type 5.
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Affiliation(s)
- Fernando Rodríguez-Ramos
- Facultad de Química, Departamento de Farmacia, Universidad Nacional Autónoma de México, México D.F., México
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Effects of amitriptyline, a tricyclic antidepressant, on smooth muscle reactivity in isolated rat trachea. J Anesth 2009; 23:385-91. [PMID: 19685119 DOI: 10.1007/s00540-009-0781-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Accepted: 04/17/2009] [Indexed: 01/16/2023]
Abstract
PURPOSE This study was designed to investigate the action of amitriptyline, a tricyclic antidepressant, on airway smooth muscle reactivity and its underlying mechanisms. METHODS In isolated rat trachea, isometric force was recorded to examine the effects of amitriptyline on the contractile response to acetylcholine (ACh), electrical field stimulation (EFS), calyculin A (a myosin light chain phosphatase inhibitor), and sphingosylphosphorylcholine (SPC; a Rhokinase activator). In addition, inositol monophosphate (IP1) accumulation was measured to examine its effects on inositol 1, 4, 5-trisphosphate (IP(3)) production during stimulation with ACh. RESULTS Amitriptyline inhibited the contractile responses to ACh, EFS, calyculin A, and SPC, with the concentrations of amitriptyline (mean +/- SD) required to exert 50% inhibition (IC(50)) being 4.3 +/- 1.3 microM, 3.2 +/- 1.6 microM, 256.4 +/- 106.4 microM, and 98.2 +/- 21.8 microM, respectively. In addition, amitriptyline (10 microM) eliminated the ACh (10 microM)-induced IP(1) accumulation. CONCLUSION The results suggest that amitriptyline does not influence tracheal smooth muscle reactivity at clinical concentrations (<1 microM), but attenuates the reactivity at supraclinical concentrations (> or =1 microM). The attenuated response to ACh brought about by amitriptyline is presumably due, at least in part, to the inhibition of phosphatidylinositol (PI) metabolism. The ability of amitriptyline to inhibit the calyculin Ainduced contraction suggests that amitriptyline also inhibits the Ca(2+)-calmodulin-myosin light chain pathway independently of the inhibition of PI metabolism. Finally, the difference between the IC(50) values for SPC-induced contraction and those for calyculin A-induced contraction suggests that amitriptyline may also inhibit the Rho-kinase pathway.
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Pelaia G, Renda T, Gallelli L, Vatrella A, Busceti MT, Agati S, Caputi M, Cazzola M, Maselli R, Marsico SA. Molecular mechanisms underlying airway smooth muscle contraction and proliferation: implications for asthma. Respir Med 2008; 102:1173-81. [PMID: 18579364 DOI: 10.1016/j.rmed.2008.02.020] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Accepted: 02/26/2008] [Indexed: 11/18/2022]
Abstract
Airway smooth muscle (ASM) plays a key role in bronchomotor tone, as well as in structural remodeling of the bronchial wall. Therefore, ASM contraction and proliferation significantly participate in the development and progression of asthma. Many contractile agonists also behave as mitogenic stimuli, thus contributing to frame a hyperresponsive and hyperplastic ASM phenotype. In this review, the molecular mechanisms and signaling pathways involved in excitation-contraction coupling and ASM cell growth will be outlined. Indeed, the recent advances in understanding the basic aspects of ASM biology are disclosing important cellular targets, currently explored for the implementation of new, more effective anti-asthma therapies.
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Affiliation(s)
- Girolamo Pelaia
- Department of Experimental and Clinical Medicine, University "Magna Graecia" of Catanzaro, Italy
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Chakrabarty K, Fahim M. Modulation of the contractile responses of guinea pig isolated tracheal rings after chronic intermittent hypobaric hypoxia with and without cold exposure. J Appl Physiol (1985) 2005; 99:1006-11. [PMID: 16103517 DOI: 10.1152/japplphysiol.01304.2004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous studies have documented that repetitive exposure to intermittent hypoxia, such as that encountered in preparation to high-altitude ascent, influences breathing. However, the impact of intermittent hypoxia on airway smooth muscle has not been explored. Ascents to high altitude, in addition to hypoxia, expose individuals to cold air. The objective of the present study is to examine the effect of chronic intermittent hypobaric hypoxia (CIH) and CIH combined with cold exposure (CIHC) on tracheal smooth muscle responses to various contractile and relaxant agonists. Experiments were performed on tracheal rings harvested from adult guinea pigs exposed either to CIH or CIHC [14 days (6 h/day) at barometric pressure of 350 mmHg with and without cold exposure of 5°C] or to room air (normoxia). CIH and CIHC attenuated maximum contractile responses to ACh compared with normoxia. The maximum contractile response to histamine decreased with CIH, whereas CIHC restored the response back to normoxia. Both CIH and CIHC attenuated maximum contractile responses to 5-HT. Altered contractile responses after CIH and CIHC were independent of epithelium. Isoproterenol-induced relaxation was not altered by CIH, whereas it was enhanced after CIHC, and these responses were independent of the epithelium. The data demonstrate that intermittent exposure to hypoxia profoundly influences contractile response of tracheal smooth muscle, and cold exposure can further modulate the response, implying the importance of cold at high altitude.
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Affiliation(s)
- Kaveri Chakrabarty
- Dept. of Physiology, Vallabhbhai Patel Chest Institute, Univ. of Delhi, Delhi-110007, India
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Tuncel BI, Sadan G. Effects of Phosphodiesterase V Inhibition on Nitric Oxide-Mediated Relaxation Responses in Guinea Pig Trachea. Pharmacology 2004; 71:102-6. [PMID: 15118349 DOI: 10.1159/000076946] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2003] [Accepted: 10/20/2003] [Indexed: 11/19/2022]
Abstract
In the present study, we aimed to evaluate the effects of PDE V inhibition on NO-mediated relaxation responses in isolated guinea pig trachea. Under the NANC conditions, tracheal preparations were contracted with histamine (100 microm/l). When contraction had reached a plateau, relaxation responses to electrical field stimulation (EFS, 60 V, 0.5 ms, 5-10 Hz) were determined before and after incubation of the tracheal ring with L-NAME (1 mmol/l), a NO synthase inhibitor. L-NAME significantly inhibited the relaxation responses and this inhibitory effect was reversed by L-arginine (1 mmol/l), a precursor of NO, but was not affected by D-arginine. In addition, cumulative application of the NO donors, 3-morpholino-sydnonimine (SIN-1) and sodium nitroprusside (SNP), caused concentration-dependent relaxation of tissues precontracted with histamine. The selective PDE type V inhibitor zaprinast at EC50 concentration (30 micromol/l) significantly potentiated EFS-induced NANC relaxations and relaxant responses to SIN-1 and SNP. In conclusion, these data support the hypothesis that NO is a mediator of NANC relaxations of guinea pig tracheal rings and PDE V inhibition potentiates NO-mediated relaxation.
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Affiliation(s)
- Başak I Tuncel
- Department of Pharmacology, Akdeniz University Faculty of Medicine, Arapsuyu, Antalya, Turkey.
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Hashimoto K, Peebles RS, Sheller JR, Jarzecka K, Furlong J, Mitchell DB, Hartert TV, Graham BS. Suppression of airway hyperresponsiveness induced by ovalbumin sensitisation and RSV infection with Y-27632, a Rho kinase inhibitor. Thorax 2002; 57:524-7. [PMID: 12037228 PMCID: PMC1746359 DOI: 10.1136/thorax.57.6.524] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Smooth muscle contraction is one of the hallmarks of asthma. A recently developed pyridine derivative, Y-27632, a selective Rho kinase inhibitor, has been reported to inhibit the smooth muscle contraction of human and animal trachea in ex vivo systems but its effect in animal models of airway hyperresponsiveness (AHR) has not been examined. The purpose of this study was to evaluate the effect of Y-27632 in a murine model of allergic and virally induced AHR. METHODS Baseline lung resistance and methacholine induced AHR were measured in mice sensitised to ovalbumin (OVA) and also in mice infected with respiratory syncytial virus (RSV) following ovalbumin sensitisation (OVA/RSV). RESULTS Time course and dose ranging experiments indicated that 30 mg/kg Y-27632 given by gavage 2 hours before methacholine challenge significantly reduced baseline lung resistance and prevented AHR in OVA sensitised mice. Y-27632 also suppressed AHR induced by the bronchospastic agent serotonin in OVA sensitised mice and prevented methacholine induced AHR in OVA/RSV mice. CONCLUSIONS These results suggest that the signalling pathway mediated through Rho kinase may have an important role in bronchial smooth muscle tone in allergen induced and virus induced AHR and should be considered as a novel target for asthma treatment.
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Affiliation(s)
- K Hashimoto
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-2582, USA
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