Science.gov

Sample records for airway muscle activity

  1. Tonic activity in inspiratory muscles during continuous negative airway pressure.

    PubMed

    Meessen, N E; van der Grinten, C P; Folgering, H T; Luijendijk, S C

    1993-05-01

    We studied tonic inspiratory activity (TIA) induced by continuous negative airway pressure (CNAP) in anaesthetized, spontaneously breathing cats. TIA in the diaphragm and parasternal intercostal muscles (ICM) was quantified in response to tracheal pressure (PTR) = -0.3 to -1.2 kPa. To differentiate between reflexes from rapidly adapting receptors (RARs), slowly adapting receptors (SARs) and C-fiber endings different temperatures of the vagus nerves (TVG) were used between 4 and 37 degrees C. At PTR = -1.2 kPa mean TIA values were 41% and 62% of peak inspiratory EMG activity of control breaths for the diaphragm and ICM, respectively. After vagotomy and for TVG < 6 degrees C CNAP did not induce TIA anymore. Changes in inspiratory and expiratory time during vagal cooling down to 4 degrees C confirmed the selective block of conductance in vagal afferents of the three types of lung receptors. We conclude that CNAP-induced TIA results from stimulation of RARs. Our data strongly indicate that stimulation of SARs suppresses TIA, whereas C-fiber endings are not involved in TIA at all. The results suggest that part of the hyperinflation in bronchial asthma may be caused by TIA in response to mechanical stimulation of RARs. PMID:8327788

  2. Lingual Muscle Activity Across Sleep–Wake States in Rats with Surgically Altered Upper Airway

    PubMed Central

    Rukhadze, Irma; Kalter, Julie; Stettner, Georg M.; Kubin, Leszek

    2014-01-01

    Obstructive sleep apnea (OSA) patients have increased upper airway muscle activity, including such lingual muscles as the genioglossus (GG), geniohyoid (GH), and hyoglossus (HG). This adaptation partially protects their upper airway against obstructions. Rodents are used to study the central neural control of sleep and breathing but they do not naturally exhibit OSA. We investigated whether, in chronically instrumented, behaving rats, disconnecting the GH and HG muscles from the hyoid (H) apparatus would result in a compensatory increase of other upper airway muscle activity (electromyogram, EMG) and/or other signs of upper airway instability. We first determined that, in intact rats, lingual (GG and intrinsic) muscles maintained stable activity levels when quantified based on 2 h-long recordings conducted on days 6 through 22 after instrumentation. We then studied five rats in which the tendons connecting the GH and HG muscles to the H apparatus were experimentally severed. When quantified across all recording days, lingual EMG during slow-wave sleep (SWS) was modestly but significantly increased in rats with surgically altered upper airway [8.6 ± 0.7% (SE) vs. 6.1 ± 0.7% of the mean during wakefulness; p = 0.012]. Respiratory modulation of lingual EMG occurred mainly during SWS and was similarly infrequent in both groups, and the incidence of sighs and central apneas also was similar. Thus, a weakened action of selected lingual muscles did not produce sleep-disordered breathing but resulted in a relatively elevated activity in other lingual muscles during SWS. These results encourage more extensive surgical manipulations with the aim to obtain a rodent model with collapsible upper airway. PMID:24803913

  3. Neostigmine but not sugammadex impairs upper airway dilator muscle activity and breathing

    PubMed Central

    Eikermann, M.; Zaremba, S.; Malhotra, A.; Jordan, A. S.; Rosow, C.; Chamberlin, N. L.

    2008-01-01

    Background Cholinesterase inhibitor-based reversal agents, given in the absence of neuromuscular block, evoke a partial upper airway obstruction by decreasing skeletal upper airway muscle function. Sugammadex reverses neuromuscular block by encapsulating rocuronium. However, its effects on upper airway integrity and breathing are unknown. Methods Fifty-one adult male rats were anaesthetized with isoflurane, tracheostomized, and a femoral artery and vein were cannulated. First, we compared the efficacy of sugammadex 15 mg kg−1 and neostigmine 0.06 mg kg−1 to reverse respiratory effects of rocuronium-induced partial paralysis [train-of-four ratio (T4/T1)=0.5]. Subsequently, we compared the safety of sugammadex and neostigmine given after recovery of the T4/T1 to 1, by measuring phasic genioglossus activity and breathing. Results During partial paralysis (T4/T1=0.5), time to recovery of minute volume to baseline values was 10.9 (2), 75.8 (18), and 153 (54) s with sugammadex, neostigmine, and placebo, respectively (sugammadex was significantly faster than neostigmine and placebo, P<0.05). Recovery of T4/T1 was also faster for sugammadex than neostigmine and placebo. Neostigmine administration after complete recovery of T4/T1 decreased upper airway dilator muscle activity to 64 (30)% of baseline and decreased tidal volume (P<0.05 for both variables), whereas sugammadex had no effect on either variable. Conclusions In contrast to neostigmine, which significantly impairs upper airway dilator muscle activity when given after recovery from neuromuscular block, a reversal dose of sugammadex given under the same conditions does not affect genioglossus muscle activity and normal breathing. Human studies will be required to evaluate the clinical relevance of our findings. PMID:18559352

  4. Effects of upper airway pressure on abdominal muscle activity in conscious dogs.

    PubMed

    Plowman, L; Lauff, D C; McNamara, F; Berthon-Jones, M; Sullivan, C E

    1991-12-01

    We have examined arousal and abdominal muscle electromyogram (EMGabd) responses to upper airway pressure stimuli during physiological sleep in four dogs with permanent side-hole tracheal stomata. The dogs were trained to sleep with a tightly fitting snout mask, hermetically sealed in place, while breathing through a cuffed endotracheal tube inserted through the tracheostomy. Sleep stage was determined by behavioral and electroencephalographic criteria. EMGabd activity was measured using bipolar fine-wire electrodes inserted into the abdominal muscle layers. Static increases or decreases in upper airway pressure (+/- 6 cmH2O), when applied at the snout mask or larynx (upper trachea), caused an immediate decrease in EMGabd on the first two to three breaths; EMGabd usually returned to control levels within the 1-min test interval. In contrast, oscillatory pressure waves at 30 Hz and +/- 3 cmH2O amplitude (or -2 to -8 cmH2O amplitude) produced an immediate and sustained reduction in IMGabd in all sleep states. Inhibition of EMGabd could be maintained over many minutes when the oscillatory pressure stimulus was pulsed by using a cycle of 0.5 s on and 0.5 s off. Oscillatory upper airway pressures were also found to be powerful arousal-promoting stimuli, producing arousal in 94% of tests in drowsiness and 66% of tests in slowwave sleep. The results demonstrate the presence of breath-by-breath upper airway control of abdominal muscle activity. PMID:1778951

  5. Influence of upper airway sensory receptors on respiratory muscle activation in humans.

    PubMed

    Redline, S; Strohl, K P

    1987-07-01

    We reasoned that neural information from upper airway (UA) sensory receptors could influence the relationship between UA and diaphragmatic neuromuscular responses to hypercapnia. In this study, the electromyographic (EMG) activities of the alae nasi (AN), genioglossus (GG), and chest wall (CW) or diaphragm (Di) to ventilatory loading were assessed in six laryngectomized, tracheostomized human subjects and in six subjects breathing with an intact UA before and after topical UA anesthesia. The EMG activities of the UA and thoracic muscles increased at similar rates with increasing hypercapnia in normal subjects, in subjects whose upper airways were anesthetized, and in laryngectomized subjects breathing with a cervical tracheostomy. Furthermore, in the laryngectomized subjects, respiratory muscle EMG activation increased with resistive inspiratory loading (15 cmH2O X l-1 X s) applied at the level of a cervical tracheostomy. At an average expired CO2 fraction of 7.0%, resistive loading resulted in a 93 +/- 26.3% (SE) increase in peak AN EMG activity, a 39 +/- 2.0% increase in peak GG EMG activity, and a 43.2 +/- 16.5% increase in peak CW (Di) EMG activity compared with control values. We conclude that the ventilatory responses of the UA and thoracic muscles to ventilatory loading are not substantially influenced by laryngectomy or UA anesthesia. PMID:3624139

  6. Genetic differences in airway smooth muscle function.

    PubMed

    Martin, James G; Jo, Taisuke

    2008-01-01

    The genetic basis for airway smooth muscle properties is poorly explored. Contraction and relaxation are altered in asthmatic airway smooth muscle, but the basis for the alterations and the role that muscle-specific susceptibility genes may play is largely unexplored. Alterations in the beta-adrenergic receptor, signaling pathways affecting inositol phosphate metabolism, adenylyl and guanylyl cyclase activity, and contractile proteins such as the myosin heavy chain are all suggested by experimental model systems. Significant changes in proliferative and secretory capacities of asthmatic smooth muscle are also demonstrated, but their genetic basis also requires elucidation. Certain asthma-related genes such as ADAM33, although potentially important for smooth muscle function, have been incompletely explored. PMID:18094088

  7. TLR3 activation increases chemokine expression in human fetal airway smooth muscle cells.

    PubMed

    Faksh, Arij; Britt, Rodney D; Vogel, Elizabeth R; Thompson, Michael A; Pandya, Hitesh C; Martin, Richard J; Pabelick, Christina M; Prakash, Y S

    2016-01-15

    Viral infections, such as respiratory syncytial virus and rhinovirus, adversely affect neonatal and pediatric populations, resulting in significant lung morbidity, including acute asthma exacerbation. Studies in adults have demonstrated that human airway smooth muscle (ASM) cells modulate inflammation through their ability to secrete inflammatory cytokines and chemokines. The role of ASM in the developing airway during infection remains undefined. In our study, we used human fetal ASM cells as an in vitro model to examine the effect of Toll-like receptor (TLR) agonists on chemokine secretion. We found that fetal ASM express multiple TLRs, including TLR3 and TLR4, which are implicated in the pathogenesis of respiratory syncytial virus and rhinovirus infection. Cells were treated with TLR agonists, polyinosinic-polycytidylic acid [poly(I:C)] (TLR3 agonist), lipopolysaccharide (TLR4 agonist), or R848 (TLR7/8 agonist), and IL-8 and chemokine (C-C motif) ligand 5 (CCL5) secretion were evaluated. Interestingly, poly(I:C), but neither lipopolysaccharide nor R848, increased IL-8 and chemokine (C-C motif) ligand 5 secretion. Examination of signaling pathways suggested that the poly(I:C) effects in fetal ASM involve TLR and ERK signaling, in addition to another major inflammatory pathway, NF-κB. Moreover, there are variations between fetal and adult ASM with respect to poly(I:C) effects on signaling pathways. Pharmacological inhibition suggested that ERK pathways mediate poly(I:C) effects. Overall, our data show that poly(I:C) initiates activation of proinflammatory pathways in developing ASM, which may contribute to immune responses to infection and exacerbation of asthma. PMID:26589477

  8. Nonadrenergic, noncholinergic responses stabilize smooth muscle tone, with and without parasympathetic activation, in guinea-pig isolated airways.

    PubMed

    Lindén, A; Löfdahl, C G; Ullman, A; Skoogh, B E

    1993-03-01

    In guinea-pig isolated airways, nonadrenergic, noncholinergic (NANC) neural responses converge towards a similar level of smooth muscle tone, via a contraction when the tone is low prior to stimulation, and via a relaxation when the tone is high prior to stimulation. We wanted to assess the effect of simultaneous parasympathetic activation on these converging NANC responses, with and without the addition of sympathetic activation. In guinea-pig isolated airways, the spontaneous airway tone was initially abolished by indomethacin (10 microM). In one series, adrenergic depletion by guanethidine (10 microM) was then established, with and without cholinergic blockade by atropine (1 microM). In another series, either cholinergic blockade by atropine (1 microM) or no blockade was utilized. Responses to electrical field stimulation (1,200 mA, 0.5 ms, 3 Hz for 240 s) were studied with no induced tone, at a moderate (0.3 microM) and at a near-maximum (6 microM), histamine-induced tone. The mean level of the tonus equilibrium (% of maximum tone) was higher with the simultaneous NANC and parasympathetic activation than with NANC activation alone (75% compared with 44%, in the main bronchus, n = 8). The level of the tonus equilibrium was also higher with the simultaneous NANC, sympathetic and parasympathetic activation than with NANC and sympathetic activation only (49% compared with 21%, in the main bronchus, n = 8). The pattern was similar in the distal trachea. In conclusion, NANC neural responses can stabilize smooth muscle tone, and this stabilizing effect can be modulated by both parasympathetic and sympathetic activation, in guinea-pig isolated airways. PMID:8472834

  9. The effect of hyperpolarization-activated cyclic nucleotide-gated ion channel inhibitors on the vagal control of guinea pig airway smooth muscle tone

    PubMed Central

    McGovern, Alice E; Robusto, Jed; Rakoczy, Joanna; Simmons, David G; Phipps, Simon; Mazzone, Stuart B

    2014-01-01

    BACKGROUND AND PURPOSE Subtypes of the hyperpolarization-activated cyclic nucleotide-gated (HCN) family of cation channels are widely expressed on nerves and smooth muscle cells in many organ systems, where they serve to regulate membrane excitability. Here we have assessed whether HCN channel inhibitors alter the function of airway smooth muscle or the neurons that regulate airway smooth muscle tone. EXPERIMENTAL APPROACH The effects of the HCN channel inhibitors ZD7288, zatebradine and Cs+ were assessed on agonist and nerve stimulation-evoked changes in guinea pig airway smooth muscle tone using tracheal strips in vitro, an innervated tracheal tube preparation ex vivo or in anaesthetized mechanically ventilated guinea pigs in vivo. HCN channel expression in airway nerves was assessed using immunohistochemistry, PCR and in situ hybridization. KEY RESULTS HCN channel inhibition did not alter airway smooth muscle reactivity in vitro to exogenously administered smooth muscle spasmogens, but significantly potentiated smooth muscle contraction evoked by the sensory nerve stimulant capsaicin and electrical field stimulation of parasympathetic cholinergic postganglionic neurons. Sensory nerve hyperresponsiveness was also evident in in vivo following HCN channel blockade. Cs+, but not ZD7288, potentiated preganglionic nerve-dependent airway contractions and over time induced autorhythmic preganglionic nerve activity, which was not mimicked by inhibitors of potassium channels. HCN channel expression was most evident in vagal sensory ganglia and airway nerve fibres. CONCLUSIONS AND IMPLICATIONS HCN channel inhibitors had a previously unrecognized effect on the neural regulation of airway smooth muscle tone, which may have implications for some patients receiving HCN channel inhibitors for therapeutic purposes. PMID:24762027

  10. Critical role of actin-associated proteins in smooth muscle contraction, cell proliferation, airway hyperresponsiveness and airway remodeling.

    PubMed

    Tang, Dale D

    2015-01-01

    Asthma is characterized by airway hyperresponsiveness and airway remodeling, which are largely attributed to increased airway smooth muscle contractility and cell proliferation. It is known that both chemical and mechanical stimulation regulates smooth muscle contraction. Recent studies suggest that contractile activation and mechanical stretch induce actin cytoskeletal remodeling in smooth muscle. However, the mechanisms that control actin cytoskeletal reorganization are not completely elucidated. This review summarizes our current understanding regarding how actin-associated proteins may regulate remodeling of the actin cytoskeleton in airway smooth muscle. In particular, there is accumulating evidence to suggest that Abelson tyrosine kinase (Abl) plays a critical role in regulating airway smooth muscle contraction and cell proliferation in vitro, and airway hyperresponsiveness and remodeling in vivo. These studies indicate that Abl may be a novel target for the development of new therapy to treat asthma. PMID:26517982

  11. Cortex phellodendri Extract Relaxes Airway Smooth Muscle

    PubMed Central

    Jiang, Qiu-Ju; Chen, Weiwei; Dan, Hong; Tan, Li; Zhu, He; Yang, Guangzhong; Shen, Jinhua; Peng, Yong-Bo; Zhao, Ping; Xue, Lu; Yu, Meng-Fei; Ma, Liqun; Si, Xiao-Tang; Wang, Zhuo; Dai, Jiapei; Qin, Gangjian; Zou, Chunbin; Liu, Qing-Hua

    2016-01-01

    Cortex phellodendri is used to reduce fever and remove dampness and toxin. Berberine is an active ingredient of C. phellodendri. Berberine from Argemone ochroleuca can relax airway smooth muscle (ASM); however, whether the nonberberine component of C. phellodendri has similar relaxant action was unclear. An n-butyl alcohol extract of C. phellodendri (NBAECP, nonberberine component) was prepared, which completely inhibits high K+- and acetylcholine- (ACH-) induced precontraction of airway smooth muscle in tracheal rings and lung slices from control and asthmatic mice, respectively. The contraction induced by high K+ was also blocked by nifedipine, a selective blocker of L-type Ca2+ channels. The ACH-induced contraction was partially inhibited by nifedipine and pyrazole 3, an inhibitor of TRPC3 and STIM/Orai channels. Taken together, our data demonstrate that NBAECP can relax ASM by inhibiting L-type Ca2+ channels and TRPC3 and/or STIM/Orai channels, suggesting that NBAECP could be developed to a new drug for relieving bronchospasm. PMID:27239213

  12. CD38 and Airway hyperresponsiveness: Studies on human airway smooth muscle cells and mouse models

    PubMed Central

    Guedes, Alonso GP; Deshpande, Deepak A; Dileepan, Mythili; Walseth, Timothy F; Panettieri, Reynold A; Subramanian, Subbaya; Kannan, Mathur S

    2015-01-01

    Asthma is an inflammatory disease in which altered calcium regulation, contractility and airway smooth muscle (ASM) proliferation contribute to airway hyperresponsiveness and airway wall remodeling. The enzymatic activity of CD38, a cell-surface protein expressed in human ASM cells, generates calcium mobilizing second messenger molecules such as cyclic ADP-ribose. CD38 expression in human ASM cells is augmented by cytokines (e.g. TNF-α) that requires activation of MAP kinases and the transcription factors, NF-ƙB and AP-1 and post-transcriptionally regulated by miR-140-3p and miR-708 by binding to 3’ Untranslated Region of CD38 as well as by modulating the activation of signaling mechanisms involved in its regulation. Mice deficient in CD38 exhibit reduced airway responsiveness to inhaled methacholine relative to response in wild-type mice. Intranasal challenge of CD38 deficient mice with TNF-α or IL-13, or the environmental fungus Alternaria alternata, causes significantly attenuated methacholine responsiveness compared to wild-type mice, with comparable airway inflammation. Reciprocal bone marrow transfer studies revealed partial restoration of airway hyperresponsiveness to inhaled methacholine in the Cd38 deficient mice. These studies provide evidence for CD38 involvement in the development of airway hyperresponsiveness, a hallmark feature of asthma. Future studies aimed at drug discovery and delivery targeting CD38 expression and/or activity are warranted. PMID:25594684

  13. Origins of increased airway smooth muscle mass in asthma.

    PubMed

    Berair, Rachid; Saunders, Ruth; Brightling, Christopher E

    2013-01-01

    Asthma is characterized by both chronic inflammation and airway remodeling. Remodeling--the structural changes seen in asthmatic airways--is pivotal in the pathogenesis of the disease. Although significant advances have been made recently in understanding the different aspects of airway remodeling, the exact biology governing these changes remains poorly understood. There is broad agreement that, in asthma, increased airway smooth muscle mass, in part due to smooth muscle hyperplasia, is a very significant component of airway remodeling. However, significant debate persists on the origins of these airway smooth muscle cells. In this review article we will explore the natural history of airway remodeling in asthma and we will discuss the possible contribution of progenitors, stem cells and epithelial cells in mesenchymal cell changes, namely airway smooth muscle hyperplasia seen in the asthmatic airways. PMID:23742314

  14. Bronchodilator and anti-inflammatory activities of glaucine: In vitro studies in human airway smooth muscle and polymorphonuclear leukocytes.

    PubMed

    Cortijo, J; Villagrasa, V; Pons, R; Berto, L; Martí-Cabrera, M; Martinez-Losa, M; Domenech, T; Beleta, J; Morcillo, E J

    1999-08-01

    1. Selective phosphodiesterase 4 (PDE4) inhibitors are of potential interest in the treatment of asthma. We examined the effects of the alkaloid S-(+)-glaucine, a PDE4 inhibitor, on human isolated bronchus and granulocyte function. 2. Glaucine selectively inhibited PDE4 from human bronchus and polymorphonuclear leukocytes (PMN) in a non-competitive manner (Ki=3.4 microM). Glaucine displaced [3H]-rolipram from its high-affinity binding sites in rat brain cortex membranes (IC50 approximately 100 microM). 3. Glaucine inhibited the spontaneous and histamine-induced tone in human isolated bronchus (pD2 approximately 4.5). Glaucine (10 microM) did not potentiate the isoprenaline-induced relaxation but augmented cyclic AMP accumulation by isoprenaline. The glaucine-induced relaxation was resistant to H-89, a protein kinase A inhibitor. Glaucine depressed the contractile responses to Ca2+ (pD'2 approximately 3.62) and reduced the sustained rise of [Ca2+]i produced by histamine in cultured human airway smooth muscle cells (-log IC50 approximately 4.3). 4. Glaucine augmented cyclic AMP levels in human polymorphonuclear leukocytes challenged with N-formyl-Met-Leu-Phe (FMLP) or isoprenaline, and inhibited FMLP-induced superoxide generation, elastase release, leukotriene B4 production, [Ca2+]i signal and platelet aggregation as well as opsonized zymosan-, phorbol myristate acetate-, and A23187-induced superoxide release. The inhibitory effect of glaucine on superoxide generation by FMLP was reduced by H-89. 5. In conclusion, Ca2+ channel antagonism by glaucine appears mainly responsible for the relaxant effect of glaucine in human isolated bronchus while PDE4 inhibition contributes to the inhibitory effects of glaucine in human granulocytes. The very low PDE4/binding site ratio found for glaucine makes this compound attractive for further structure-activity studies. PMID:10455321

  15. Bronchodilator and anti-inflammatory activities of glaucine: In vitro studies in human airway smooth muscle and polymorphonuclear leukocytes

    PubMed Central

    Cortijo, J; Villagrasa, V; Pons, R; Berto, L; Martí-Cabrera, M; Martinez-Losa, M; Domenech, T; Beleta, J; Morcillo, E J

    1999-01-01

    Selective phosphodiesterase 4 (PDE4) inhibitors are of potential interest in the treatment of asthma. We examined the effects of the alkaloid S-(+)-glaucine, a PDE4 inhibitor, on human isolated bronchus and granulocyte function.Glaucine selectively inhibited PDE4 from human bronchus and polymorphonuclear leukocytes (PMN) in a non-competitive manner (Ki=3.4 μM). Glaucine displaced [3H]-rolipram from its high-affinity binding sites in rat brain cortex membranes (IC50∼100 μM).Glaucine inhibited the spontaneous and histamine-induced tone in human isolated bronchus (pD2∼4.5). Glaucine (10 μM) did not potentiate the isoprenaline-induced relaxation but augmented cyclic AMP accumulation by isoprenaline. The glaucine-induced relaxation was resistant to H-89, a protein kinase A inhibitor. Glaucine depressed the contractile responses to Ca2+ (pD'2∼3.62) and reduced the sustained rise of [Ca2+]i produced by histamine in cultured human airway smooth muscle cells (−log IC50∼4.3).Glaucine augmented cyclic AMP levels in human polymorphonuclear leukocytes challenged with N-formyl-Met-Leu-Phe (FMLP) or isoprenaline, and inhibited FMLP-induced superoxide generation, elastase release, leukotriene B4 production, [Ca2+]i signal and platelet aggregation as well as opsonized zymosan-, phorbol myristate acetate-, and A23187-induced superoxide release. The inhibitory effect of glaucine on superoxide generation by FMLP was reduced by H-89.In conclusion, Ca2+ channel antagonism by glaucine appears mainly responsible for the relaxant effect of glaucine in human isolated bronchus while PDE4 inhibition contributes to the inhibitory effects of glaucine in human granulocytes. The very low PDE4/binding site ratio found for glaucine makes this compound attractive for further structure-activity studies. PMID:10455321

  16. Emergence of airway smooth muscle functions related to structural malleability

    PubMed Central

    Fredberg, Jeffrey J.

    2011-01-01

    The function of a complex system such as a smooth muscle cell is the result of the active interaction among molecules and molecular aggregates. Emergent macroscopic manifestations of these molecular interactions, such as the length-force relationship and its associated length adaptation, are well documented, but the molecular constituents and organization that give rise to these emergent muscle behaviors remain largely unknown. In this minireview, we describe emergent properties of airway smooth muscle that seem to have originated from inherent fragility of the cellular structures, which has been increasingly recognized as a unique and important smooth muscle attribute. We also describe molecular interactions (based on direct and indirect evidence) that may confer malleability on fragile structural elements that in turn may allow the muscle to adapt to large and frequent changes in cell dimensions. Understanding how smooth muscle works may hinge on how well we can relate molecular events to its emergent macroscopic functions. PMID:21127211

  17. Effects of tracheal airway occlusion on hyoid muscle length and upper airway volume.

    PubMed

    van Lunteren, E; Haxhiu, M A; Cherniack, N S

    1989-12-01

    Complex relationships exist among electromyograms (EMGs) of the upper airway muscles, respective changes in muscle length, and upper airway volume. To test the effects of preventing lung inflation on these relationships, recordings were made of EMGs and length changes of the geniohyoid (GH) and sternohyoid (SH) muscles as well as of tidal changes in upper airway volume in eight anesthetized cats. During resting breathing, tracheal airway occlusion tended to increase the inspiratory lengthening of GH and SH. In response to progressive hypercapnia, the GH eventually shortened during inspiration in all animals; the extent of muscle shortening was minimally augmented by airway occlusion despite substantial increases in EMGs. SH lengthened during inspiration in six of eight animals under hypercapnic conditions, and in these cats lengthening was greater during airway occlusion even though EMGs increased. Despite the above effects on SH and GH length, upper airway tidal volume was increased significantly by tracheal occlusion under hypercapnic conditions. These data suggest that the thoracic and upper airway muscle reflex effects of preventing lung inflation during inspiration act antagonistically on hyoid muscle length, but, because of the mechanical arrangement of the hyoid muscles relative to the airway and thorax, they act agonistically to augment tidal changes in upper airway volume. The augmentation of upper airway tidal volume may occur in part as a result of the effects of thoracic movements being passively transmitted through the hyoid muscles. PMID:2606835

  18. Calcineurin/Nuclear Factor of Activated T Cells–Coupled Vanilliod Transient Receptor Potential Channel 4 Ca2+ Sparklets Stimulate Airway Smooth Muscle Cell Proliferation

    PubMed Central

    Zhao, Limin; Sullivan, Michelle N.; Chase, Marlee; Gonzales, Albert L.

    2014-01-01

    Proliferation of airway smooth muscle cells (ASMCs) contributes to the remodeling and irreversible obstruction of airways during severe asthma, but the mechanisms underlying this disease process are poorly understood. Here we tested the hypothesis that Ca2+ influx through the vanilliod transient receptor potential channel (TRPV) 4 stimulates ASMC proliferation. We found that synthetic and endogenous TRPV4 agonists increase proliferation of primary ASMCs. Furthermore, we demonstrate that Ca2+ influx through individual TRPV4 channels produces Ca2+ microdomains in ASMCs, called “TRPV4 Ca2+ sparklets.” We also show that TRPV4 channels colocalize with the Ca2+/calmodulin–dependent protein phosphatase calcineurin in ASMCs. Activated calcineurin dephosphorylates nuclear factor of activated T cells (NFAT) transcription factors cytosolic (c) to allow nuclear translocation and activation of synthetic transcriptional pathways. We show that ASMC proliferation in response to TRPV4 activity is associated with calcineurin-dependent nuclear translocation of the NFATc3 isoform tagged with green florescent protein. Our findings suggest that Ca2+ microdomains created by TRPV4 Ca2+ sparklets activate calcineurin to stimulate nuclear translocation of NFAT and ASMC proliferation. These findings further suggest that inhibition of TRPV4 could diminish asthma-induced airway remodeling. PMID:24392954

  19. Impact of obstructive apnea syndrome on upper airway respiratory muscles.

    PubMed

    Svanborg, Eva

    2005-07-28

    This article reviews studies of upper airway muscles in humans, with emphasis on muscle fiber structural and electrophysiological changes observed in patients with obstructive sleep apnea syndrome (OSAS). The concept of OSAS as a progressive disease is discussed and also possible causes. These include local nervous lesions in the upper airway, both motor and sensory. Previous muscle biopsy studies have given evidence for motor neuron lesions such as, e.g., the phenomenon of type grouping in histological sections. New data obtained with concentric needle EMG recordings from the palatopharyngeus muscles are also presented. In 10/12 OSAS patients there were typical findings indicating motor neuropathy (reduced EMG activity at maximal voluntary effort, long and polyphasic motor-unit potentials and, in two cases, spontaneous denervation activity), whereas such findings were only present in 3/15 patients with habitual snoring. This supports the hypothesis that progression from habitual snoring to the clinical disease of OSAS could be attributed to peripheral neurogenic lesions. PMID:16054444

  20. Mechanisms of BDNF regulation in asthmatic airway smooth muscle.

    PubMed

    Aravamudan, Bharathi; Thompson, Michael A; Pabelick, Christina M; Prakash, Y S

    2016-08-01

    Brain-derived neurotrophic factor (BDNF), a neurotrophin produced by airway smooth muscle (ASM), enhances inflammation effects on airway contractility, supporting the idea that locally produced growth factors influence airway diseases such as asthma. We endeavored to dissect intrinsic mechanisms regulating endogenous, as well as inflammation (TNF-α)-induced BDNF secretion in ASM of nonasthmatic vs. asthmatic humans. We focused on specific Ca(2+) regulation- and inflammation-related signaling cascades and quantified BDNF secretion. We find that TNF-α enhances BDNF release by ASM cells, via several mechanisms relevant to asthma, including transient receptor potential channels TRPC3 and TRPC6 (but not TRPC1), ERK 1/2, PI3K, PLC, and PKC cascades, Rho kinase, and transcription factors cAMP response element binding protein and nuclear factor of activated T cells. Basal BDNF expression and secretion are elevated in asthmatic ASM and increase further with TNF-α exposure, involving many of these regulatory mechanisms. We conclude that airway BDNF secretion is regulated at multiple levels, providing a basis for autocrine effects of BDNF under conditions of inflammation and disease, with potential downstream influences on contractility and remodeling. PMID:27317689

  1. Airway smooth muscle dynamics: a common pathway of airway obstruction in asthma

    PubMed Central

    An, S.S.; Bai, T.R.; Bates, J.H.T.; Black, J.L.; Brown, R.H.; Brusasco, V.; Chitano, P.; Deng, L.; Dowell, M.; Eidelman, D.H.; Fabry, B.; Fairbank, N.J.; Ford, L.E.; Fredberg, J.J.; Gerthoffer, W.T.; Gilbert, S.H.; Gosens, R.; Gunst, S.J.; Halayko, A.J.; Ingram, R.H.; Irvin, C.G.; James, A.L.; Janssen, L.J.; King, G.G.; Knight, D.A.; Lauzon, A.M.; Lakser, O.J.; Ludwig, M.S.; Lutchen, K.R.; Maksym, G.N.; Martin, J.G.; Mauad, T.; McParland, B.E.; Mijailovich, S.M.; Mitchell, H.W.; Mitchell, R.W.; Mitzner, W.; Murphy, T.M.; Paré, P.D.; Pellegrino, R.; Sanderson, M.J.; Schellenberg, R.R.; Seow, C.Y.; Silveira, P.S.P.; Smith, P.G.; Solway, J.; Stephens, N.L.; Sterk, P.J.; Stewart, A.G.; Tang, D.D.; Tepper, R.S.; Tran, T.; Wang, L.

    2008-01-01

    Excessive airway obstruction is the cause of symptoms and abnormal lung function in asthma. As airway smooth muscle (ASM) is the effecter controlling airway calibre, it is suspected that dysfunction of ASM contributes to the pathophysiology of asthma. However, the precise role of ASM in the series of events leading to asthmatic symptoms is not clear. It is not certain whether, in asthma, there is a change in the intrinsic properties of ASM, a change in the structure and mechanical properties of the noncontractile components of the airway wall, or a change in the interdependence of the airway wall with the surrounding lung parenchyma. All these potential changes could result from acute or chronic airway inflammation and associated tissue repair and remodelling. Anti-inflammatory therapy, however, does not “cure” asthma, and airway hyperresponsiveness can persist in asthmatics, even in the absence of airway inflammation. This is perhaps because the therapy does not directly address a fundamental abnormality of asthma, that of exaggerated airway narrowing due to excessive shortening of ASM. In the present study, a central role for airway smooth muscle in the pathogenesis of airway hyperresponsiveness in asthma is explored. PMID:17470619

  2. Airway smooth muscle in the pathophysiology and treatment of asthma

    PubMed Central

    Solway, Julian

    2013-01-01

    Airway smooth muscle (ASM) plays an integral part in the pathophysiology of asthma. It is responsible for acute bronchoconstriction, which is potentiated by constrictor hyperresponsiveness, impaired relaxation and length adaptation. ASM also contributes to airway remodeling and inflammation in asthma. In light of this, ASM is an important target in the treatment of asthma. PMID:23305987

  3. Bronchospasm and its biophysical basis in airway smooth muscle

    PubMed Central

    Fredberg, Jeffrey J

    2004-01-01

    Airways hyperresponsiveness is a cardinal feature of asthma but remains unexplained. In asthma, the airway smooth muscle cell is the key end-effector of bronchospasm and acute airway narrowing, but in just the past five years our understanding of the relationship of responsiveness to muscle biophysics has dramatically changed. It has become well established, for example, that muscle length is equilibrated dynamically rather than statically, and that non-classical features of muscle biophysics come to the forefront, including unanticipated interactions between the muscle and its time-varying load, as well as the ability of the muscle cell to adapt rapidly to changes in its dynamic microenvironment. These newly discovered phenomena have been described empirically, but a mechanistic basis to explain them is only beginning to emerge. PMID:15084229

  4. [Influence of nanosize particles of cobalt ferrite on contractile responses of smooth muscle segment of airways].

    PubMed

    Kapilevich, L V; Zaĭtseva, T N; Nosarev, A V; D'iakova, E Iu; Petlina, Z R; Ogorodova, L M; Ageev, B G; Magaeva, A A; Itin, V I; Terekhova, O G; Medvedev, M A

    2012-02-01

    Contractile responses of airways segments of porpoises inhaling nanopowder CoFe2O4 were stidued by means of a mechanographic method. Inhalation of the nanosize particles of CoFe2O4 in vivo and in vitro testing the nanomaterial on isolated smooth muscles led to potentiation histaminergic, cholinergic contractile activity in airways of porpoises and to strengthening of adrenergic relaxing answers. Nanosize particles vary amplitude of hyperpotassium reductions in smooth muscle segments of airways similarly to the effect of depolymerizing drug colchicine. PMID:22650066

  5. Activity of the oxidation products of oleum terebinthinae "Landes" on guinea pig airway smooth muscle in vivo and in vitro.

    PubMed

    Bermudez, J; Burgess, M F; Cassidy, F; Clarke, G D

    1987-11-01

    The oxidation products of Oleum Terebinthinae "Landes" (Ozothin; in the following briefly called Ox. O. T. L.) have been described in many studies as being of benefit in the treatment of disturbed tracheobronchial function in obstructive airways diseases. Previous literature has dealt mainly with the influence of Ox. O. T. L. on the visco-elastic properties of mucus. However, the purpose of the present work was to study the bronchospasmolytic component. Using a standard methodology for the measurement of bronchospasmolytic effects, it could be demonstrated that Ox.O.T.L., given orally or as an aerosol, protected conscious guinea pigs against histamine-induced bronchoconstriction. The potency was lower than that of isoprenaline but was significant and reproducible. These results in vivo are paralleled by effects observed on guinea pig lung strips and tracheal spiral preparations. Ox.O.T.L. relaxed, in a dose-dependent fashion, guinea pig lung strip preparations contracted with histamine. Potency and efficacy was, however, less than that of isoprenaline. Similarly, in guinea pig tracheal spiral preparations, Ox.O.T.L. was less potent than isoprenaline in counteracting carbachol-elevated tone. However, efficacy equalled that of isoprenaline. Ox.O.T.L. was approximately 3 times more potent in the isolated tracheal spiral preparation than in lung strips. The activity of non-oxidised turpentine oil and terpin hydrate against histamine-induced bronchoconstriction in conscious animals and in the isolated organ preparations was substantially lower than that of the oxidation products of O.T.L. PMID:3440034

  6. Pulmonary surfactant in the airway physiology: a direct relaxing effect on the smooth muscle.

    PubMed

    Calkovska, A; Uhliarova, B; Joskova, M; Franova, S; Kolomaznik, M; Calkovsky, V; Smolarova, S

    2015-04-01

    Beside alveoli, surface active material plays an important role in the airway physiology. In the upper airways it primarily serves in local defense. Lower airway surfactant stabilizes peripheral airways, provides the transport and defense, has barrier and anti-edematous functions, and possesses direct relaxant effect on the smooth muscle. We tested in vitro the effect of two surfactant preparations Curosurf® and Alveofact® on the precontracted smooth muscle of intra- and extra-pulmonary airways. Relaxation was more pronounced for lung tissue strip containing bronchial smooth muscle as the primary site of surfactant effect. The study does not confirm the participation of ATP-dependent potassium channels and cAMP-regulated epithelial chloride channels known as CFTR chloride channels, or nitric oxide involvement in contractile response of smooth muscle to surfactant.By controlling wall thickness and airway diameter, pulmonary surfactant is an important component of airway physiology. Thus, surfactant dysfunction may be included in pathophysiology of asthma, COPD, or other diseases with bronchial obstruction. PMID:25583659

  7. Airway smooth muscle responsiveness from dogs with airway hyperresponsiveness after O/sub 3/ inhalation

    SciTech Connect

    Jones, G.L.; O'Byrne, P.M.; Pashley, M.; Serio, R.; Jury, J.; Lane, C.G.; Daniel, E.E.

    1988-07-01

    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.

  8. IL-6 trans-signaling increases expression of airways disease genes in airway smooth muscle.

    PubMed

    Robinson, Mac B; Deshpande, Deepak A; Chou, Jeffery; Cui, Wei; Smith, Shelly; Langefeld, Carl; Hastie, Annette T; Bleecker, Eugene R; Hawkins, Gregory A

    2015-07-15

    Genetic data suggest that IL-6 trans-signaling may have a pathogenic role in the lung; however, the effects of IL-6 trans-signaling on lung effector cells have not been investigated. In this study, human airway smooth muscle (HASM) cells were treated with IL-6 (classical) or IL-6+sIL6R (trans-signaling) for 24 h and gene expression was measured by RNAseq. Intracellular signaling and transcription factor activation were assessed by Western blotting and luciferase assay, respectively. The functional effect of IL-6 trans-signaling was determined by proliferation assay. IL-6 trans-signaling had no effect on phosphoinositide-3 kinase and Erk MAP kinase pathways in HASM cells. Both classical and IL-6 trans-signaling in HASM involves activation of Stat3. However, the kinetics of Stat3 phosphorylation by IL-6 trans-signaling was different than classical IL-6 signaling. This was further reflected in the differential gene expression profile by IL-6 trans-signaling in HASM cells. Under IL-6 trans-signaling conditions 36 genes were upregulated, including PLA2G2A, IL13RA1, MUC1, and SOD2. Four genes, including CCL11, were downregulated at least twofold. The expression of 112 genes was divergent between IL-6 classical and trans-signaling, including the genes HILPDA, NNMT, DAB2, MUC1, WWC1, and VEGFA. Pathway analysis revealed that IL-6 trans-signaling induced expression of genes involved in regulation of airway remodeling, immune response, hypoxia, and glucose metabolism. Treatment of HASM cells with IL-6+sIL6R induced proliferation in a dose-dependent fashion, suggesting a role for IL-6 trans-signaling in asthma pathogenesis. These novel findings demonstrate differential effect of IL-6 trans-signaling on airway cells and identify IL-6 trans-signaling as a potential modifier of airway inflammation and remodeling. PMID:26001777

  9. Short-term variability in respiratory impedance and effect of deep breath in asthmatic and healthy subjects with airway smooth muscle activation and unloading.

    PubMed

    Gobbi, Alessandro; Pellegrino, Riccardo; Gulotta, Carlo; Antonelli, Andrea; Pompilio, Pasquale; Crimi, Claudia; Torchio, Roberto; Dutto, Luca; Parola, Paolo; Dellacà, Raffaele L; Brusasco, Vito

    2013-09-01

    Inspiratory resistance (RINSP) and reactance (XINSP) were measured for 7 min at 5 Hz in 10 subjects with mild asymptomatic asthma and 9 healthy subjects to assess the effects of airway smooth muscle (ASM) activation by methacholine (MCh) and unloading by chest wall strapping (CWS) on the variability of lung function and the effects of deep inspiration (DI). Subjects were studied at control conditions, after MCh, with CWS, and after MCh with CWS. In all experimental conditions XINSP was significantly more negative in subjects with asthma than in healthy subjects, suggesting greater inhomogeneity in the former. However, the variability in both RINSP and XINSP was increased by either ASM activation or CWS, without significant difference between groups. DI significantly reversed MCh-induced changes in RINSP both in subjects with asthma and healthy subjects, but XINSP in the former only. This effect was impaired by CWS more in subjects with asthma than in healthy subjects. The velocity of RINSP and XINSP recovery after DI was faster in subjects with asthma than healthy subjects. In conclusion, these results support the opinion that the short-term variability in respiratory impedance is related to ASM tone or operating length, rather than to the disease. Nevertheless, ASM in individuals with asthma differs from that in healthy individuals in an increased velocity of shortening and a reduced sensitivity to mechanical stress when strain is reduced. PMID:23766502

  10. Functional effects of KCNQ K+ channels in airway smooth muscle

    PubMed Central

    Evseev, Alexey I.; Semenov, Iurii; Archer, Crystal R.; Medina, Jorge L.; Dube, Peter H.; Shapiro, Mark S.; Brenner, Robert

    2013-01-01

    KCNQ (Kv7) channels underlie a voltage-gated K+ current best known for control of neuronal excitability, and its inhibition by Gq/11-coupled, muscarinic signaling. Studies have indicated expression of KCNQ channels in airway smooth muscle (ASM), a tissue that is predominantly regulated by muscarinic receptor signaling. Therefore, we investigated the function of KCNQ channels in rodent ASM and their interplay with Gq/11-coupled M3 muscarinic receptors. Perforated-patch clamp of dissociated ASM cells detected a K+ current inhibited by the KCNQ antagonist, XE991, and augmented by the specific agonist, flupirtine. KCNQ channels begin to activate at voltages near resting potentials for ASM cells, and indeed XE991 depolarized resting membrane potentials. Muscarinic receptor activation inhibited KCNQ current weakly (~20%) at concentrations half-maximal for contractions. Thus, we were surprised to see that KCNQ had no affect on membrane voltage or muscle contractility following muscarinic activation. Further, M3 receptor-specific antagonist J104129 fumarate alone did not reveal KCNQ effects on muscarinic evoked depolarization or contractility. However, a role for KCNQ channels was revealed when BK-K+ channel activities are reduced. While KCNQ channels do control resting potentials, they appear to play a redundant role with BK calcium-activated K+ channels during ASM muscarinic signaling. In contrast to effect of antagonist, we observe that KCNQ agonist flupirtine caused a significant hyperpolarization and reduced contraction in vitro irrespective of muscarinic activation. Using non-invasive whole animal plethysmography, the clinically approved KCNQ agonist retigabine caused a transient reduction in indexes of airway resistance in both wild type and BK β1 knockout (KO) mice treated with the muscarinic agonist. These findings indicate that KCNQ channels can be recruited via agonists to oppose muscarinic evoked contractions and may be of therapeutic value as bronchodilators

  11. Functional effects of KCNQ K(+) channels in airway smooth muscle.

    PubMed

    Evseev, Alexey I; Semenov, Iurii; Archer, Crystal R; Medina, Jorge L; Dube, Peter H; Shapiro, Mark S; Brenner, Robert

    2013-01-01

    KCNQ (Kv7) channels underlie a voltage-gated K(+) current best known for control of neuronal excitability, and its inhibition by Gq/11-coupled, muscarinic signaling. Studies have indicated expression of KCNQ channels in airway smooth muscle (ASM), a tissue that is predominantly regulated by muscarinic receptor signaling. Therefore, we investigated the function of KCNQ channels in rodent ASM and their interplay with Gq/11-coupled M3 muscarinic receptors. Perforated-patch clamp of dissociated ASM cells detected a K(+) current inhibited by the KCNQ antagonist, XE991, and augmented by the specific agonist, flupirtine. KCNQ channels begin to activate at voltages near resting potentials for ASM cells, and indeed XE991 depolarized resting membrane potentials. Muscarinic receptor activation inhibited KCNQ current weakly (~20%) at concentrations half-maximal for contractions. Thus, we were surprised to see that KCNQ had no affect on membrane voltage or muscle contractility following muscarinic activation. Further, M3 receptor-specific antagonist J104129 fumarate alone did not reveal KCNQ effects on muscarinic evoked depolarization or contractility. However, a role for KCNQ channels was revealed when BK-K(+) channel activities are reduced. While KCNQ channels do control resting potentials, they appear to play a redundant role with BK calcium-activated K(+) channels during ASM muscarinic signaling. In contrast to effect of antagonist, we observe that KCNQ agonist flupirtine caused a significant hyperpolarization and reduced contraction in vitro irrespective of muscarinic activation. Using non-invasive whole animal plethysmography, the clinically approved KCNQ agonist retigabine caused a transient reduction in indexes of airway resistance in both wild type and BK β1 knockout (KO) mice treated with the muscarinic agonist. These findings indicate that KCNQ channels can be recruited via agonists to oppose muscarinic evoked contractions and may be of therapeutic value as

  12. Epithelium-generated neuropeptide Y induces smooth muscle contraction to promote airway hyperresponsiveness.

    PubMed

    Li, Shanru; Koziol-White, Cynthia; Jude, Joseph; Jiang, Meiqi; Zhao, Hengjiang; Cao, Gaoyuan; Yoo, Edwin; Jester, William; Morley, Michael P; Zhou, Su; Wang, Yi; Lu, Min Min; Panettieri, Reynold A; Morrisey, Edward E

    2016-05-01

    Asthma is one of the most common chronic diseases globally and can be divided into presenting with or without an immune response. Current therapies have little effect on nonimmune disease, and the mechanisms that drive this type of asthma are poorly understood. Here, we have shown that loss of the transcription factors forkhead box P1 (Foxp1) and Foxp4, which are critical for lung epithelial development, in the adult airway epithelium evokes a non-Th2 asthma phenotype that is characterized by airway hyperresponsiveness (AHR) without eosinophilic inflammation. Transcriptome analysis revealed that loss of Foxp1 and Foxp4 expression induces ectopic expression of neuropeptide Y (Npy), which has been reported to be present in the airways of asthma patients, but whose importance in disease pathogenesis remains unclear. Treatment of human lung airway explants with recombinant NPY increased airway contractility. Conversely, loss of Npy in Foxp1- and Foxp4-mutant airway epithelium rescued the AHR phenotype. We determined that NPY promotes AHR through the induction of Rho kinase activity and phosphorylation of myosin light chain, which induces airway smooth muscle contraction. Together, these studies highlight the importance of paracrine signals from the airway epithelium to the underlying smooth muscle to induce AHR and suggest that therapies targeting epithelial induction of this phenotype may prove useful in treatment of noneosinophilic asthma. PMID:27088802

  13. Inositol 1,4,5-trisphosphate activates TRPC3 channels to cause extracellular Ca2+ influx in airway smooth muscle cells.

    PubMed

    Song, Tengyao; Hao, Qiongyu; Zheng, Yun-Min; Liu, Qing-Hua; Wang, Yong-Xiao

    2015-12-15

    Transient receptor potential-3 (TRPC3) channels play a predominant role in forming nonselective cation channels (NSCCs) in airway smooth muscle cells (ASMCs) and are significantly increased in their activity and expression in asthmatic ASMCs. To extend these novel findings, we have explored the regulatory mechanisms that control the activity of TRPC3 channels. Our data for the first time reveal that inositol 1,4,5-trisphosphate (IP3), an important endogenous signaling molecule, can significantly enhance the activity of single NSCCs in ASMCs. The analog of diacylglycerol (DAG; another endogenous signaling molecule), 1-oleyl-2-acetyl-sn-glycerol (OAG), 1-stearoyl-2-arachidonoyl-sn-glycerol (SAG), and 1-stearoyl-2-linoleoyl-sn-glycerol (SLG) all augment NSCC activity. The effects of IP3 and OAG are fully abolished by lentiviral short-hairpin (sh)RNA-mediated TRPC3 channel knockdown (KD). The stimulatory effect of IP3 is eliminated by heparin, an IP3 receptor (IP3R) antagonist that blocks the IP3-binding site, but not by xestospongin C, the IP3R antagonist that has no effect on the IP3-binding site. Lentiviral shRNA-mediated KD of IP3R1, IP3R2, or IP3R3 does not alter the excitatory effect of IP3. TRPC3 channel KD greatly inhibits IP3-induced increase in intracellular Ca(2+) concentration. IP3R1 KD produces a similar inhibitory effect. TRPC3 channel and IP3R1 KD both diminish the muscarinic receptor agonist methacholine-evoked Ca(2+) responses. Taking these findings together, we conclude that IP3, the important intracellular second messenger, may activate TRPC3 channels to cause extracellular Ca(2+) influx, in addition to opening IP3Rs to induce intracellular Ca(2+) release. This novel extracellular Ca(2+) entry route may play a significant role in mediating IP3-mediated numerous cellular responses in ASMCs and other cells. PMID:26453517

  14. Theophylline Represses IL-8 Secretion from Airway Smooth Muscle Cells Independently of Phosphodiesterase Inhibition. Novel Role as a Protein Phosphatase 2A Activator.

    PubMed

    Patel, Brijeshkumar S; Rahman, Md Mostafizur; Rumzhum, Nowshin N; Oliver, Brian G; Verrills, Nicole M; Ammit, Alaina J

    2016-06-01

    Theophylline is an old drug experiencing a renaissance owing to its beneficial antiinflammatory effects in chronic respiratory diseases, such as asthma and chronic obstructive pulmonary disease. Multiple modes of antiinflammatory action have been reported, including inhibition of the enzymes that degrade cAMP-phosphodiesterase (PDE). Using primary cultures of airway smooth muscle (ASM) cells, we recently revealed that PDE4 inhibitors can potentiate the antiinflammatory action of β2-agonists by augmenting cAMP-dependent expression of the phosphatase that deactivates mitogen-activated protein kinase (MAPK)-MAPK phosphatase (MKP)-1. Therefore, the aim of this study was to address whether theophylline repressed cytokine production in a similar, PDE-dependent, MKP-1-mediated manner. Notably, theophylline did not potentiate cAMP release from ASM cells treated with the long-acting β2-agonist formoterol. Moreover, theophylline (0.1-10 μM) did not increase formoterol-induced MKP-1 messenger RNA expression nor protein up-regulation, consistent with the lack of cAMP generation. However, theophylline (at 10 μM) was antiinflammatory and repressed secretion of the neutrophil chemoattractant cytokine IL-8, which is produced in response to TNF-α. Because theophylline's effects were independent of PDE4 inhibition or antiinflammatory MKP-1, we then wished to elucidate the novel mechanisms responsible. We investigated the impact of theophylline on protein phosphatase (PP) 2A, a master controller of multiple inflammatory signaling pathways, and show that theophylline increases TNF-α-induced PP2A activity in ASM cells. Confirmatory results were obtained in A549 lung epithelial cells. PP2A activators have beneficial effects in ex vivo and in vivo models of respiratory disease. Thus, our study is the first to link theophylline with PP2A activation as a novel mechanism to control respiratory inflammation. PMID:26574643

  15. Airway smooth muscle in airway reactivity and remodeling: what have we learned?

    PubMed Central

    2013-01-01

    It is now established that airway smooth muscle (ASM) has roles in determining airway structure and function, well beyond that as the major contractile element. Indeed, changes in ASM function are central to the manifestation of allergic, inflammatory, and fibrotic airway diseases in both children and adults, as well as to airway responses to local and environmental exposures. Emerging evidence points to novel signaling mechanisms within ASM cells of different species that serve to control diverse features, including 1) [Ca2+]i contractility and relaxation, 2) cell proliferation and apoptosis, 3) production and modulation of extracellular components, and 4) release of pro- vs. anti-inflammatory mediators and factors that regulate immunity as well as the function of other airway cell types, such as epithelium, fibroblasts, and nerves. These diverse effects of ASM “activity” result in modulation of bronchoconstriction vs. bronchodilation relevant to airway hyperresponsiveness, airway thickening, and fibrosis that influence compliance. This perspective highlights recent discoveries that reveal the central role of ASM in this regard and helps set the stage for future research toward understanding the pathways regulating ASM and, in turn, the influence of ASM on airway structure and function. Such exploration is key to development of novel therapeutic strategies that influence the pathophysiology of diseases such as asthma, chronic obstructive pulmonary disease, and pulmonary fibrosis. PMID:24142517

  16. Epithelial modulation of preterm airway smooth muscle contraction.

    PubMed

    Panitch, H B; Wolfson, M R; Shaffer, T H

    1993-03-01

    To determine if epithelium from immature airways can modulate the responsiveness of smooth muscle, we studied paired trachealis muscle strips from preterm sheep. The epithelium was removed from one strip and left undisturbed in the other. Concentration-effect (CE) curves to acetylcholine (ACh), KCl, and isoproterenol were obtained. To evaluate maturational effects, responses to ACh and isoproterenol were studied in trachealis strips from adult airways. Maximal stress (Po) to ACh increased after epithelium removal in preterm (P < 0.05) but not adult strips. Epithelium removal caused a leftward shift of the ACh CE curves in both preterm and adult strips (P < 0.001) and a decrease in the dose required to achieve a one-half maximal response (ED50) in both preterm (P < 0.005) and adult strips (P < 0.05). The magnitude of the change in Po as well as in the ED50 for ACh between preterms and adults was similar. Epithelium removal did not alter either the Po or the CE curves of preterm strips stimulated by KCl. Response to isoproterenol in precontracted strips was enhanced in the presence of an intact epithelium in both groups (P < 0.05). These data demonstrate that preterm airway epithelium is able to modulate the responsiveness of smooth muscle. Additionally, the magnitude of the effect is unchanged with maturation. We speculate that damage of airway epithelium from mechanical ventilation may contribute to the increased incidence of airway hyperreactivity observed in preterm infants. PMID:8482688

  17. Airway hyperresponsiveness; smooth muscle as the principal actor

    PubMed Central

    Lauzon, Anne-Marie; Martin, James G.

    2016-01-01

    Airway hyperresponsiveness (AHR) is a defining characteristic of asthma that refers to the capacity of the airways to undergo exaggerated narrowing in response to stimuli that do not result in comparable degrees of airway narrowing in healthy subjects. Airway smooth muscle (ASM) contraction mediates airway narrowing, but it remains uncertain as to whether the smooth muscle is intrinsically altered in asthmatic subjects or is responding abnormally as a result of the milieu in which it sits. ASM in the trachea or major bronchi does not differ in its contractile characteristics in asthmatics, but the more pertinent peripheral airways await complete exploration. The mass of ASM is increased in many but not all asthmatics and therefore cannot be a unifying hypothesis for AHR, although when increased in mass it may contribute to AHR. The inability of a deep breath to reverse or prevent bronchial narrowing in asthma may reflect an intrinsic difference in the mechanisms that lead to softening of contracted ASM when subjected to stretch. Cytokines such as interleukin-13 and tumor necrosis factor-α promote a more contractile ASM phenotype. The composition and increased stiffness of the matrix in which ASM is embedded promotes a more proliferative and pro-inflammatory ASM phenotype, but the expected dedifferentiation and loss of contractility have not been shown. Airway epithelium may drive ASM proliferation and/or molecular remodeling in ways that may lead to AHR. In conclusion, AHR is likely multifactorial in origin, reflecting the plasticity of ASM properties in the inflammatory environment of the asthmatic airway. PMID:26998246

  18. Airway hyperresponsiveness; smooth muscle as the principal actor.

    PubMed

    Lauzon, Anne-Marie; Martin, James G

    2016-01-01

    Airway hyperresponsiveness (AHR) is a defining characteristic of asthma that refers to the capacity of the airways to undergo exaggerated narrowing in response to stimuli that do not result in comparable degrees of airway narrowing in healthy subjects. Airway smooth muscle (ASM) contraction mediates airway narrowing, but it remains uncertain as to whether the smooth muscle is intrinsically altered in asthmatic subjects or is responding abnormally as a result of the milieu in which it sits. ASM in the trachea or major bronchi does not differ in its contractile characteristics in asthmatics, but the more pertinent peripheral airways await complete exploration. The mass of ASM is increased in many but not all asthmatics and therefore cannot be a unifying hypothesis for AHR, although when increased in mass it may contribute to AHR. The inability of a deep breath to reverse or prevent bronchial narrowing in asthma may reflect an intrinsic difference in the mechanisms that lead to softening of contracted ASM when subjected to stretch. Cytokines such as interleukin-13 and tumor necrosis factor-α promote a more contractile ASM phenotype. The composition and increased stiffness of the matrix in which ASM is embedded promotes a more proliferative and pro-inflammatory ASM phenotype, but the expected dedifferentiation and loss of contractility have not been shown. Airway epithelium may drive ASM proliferation and/or molecular remodeling in ways that may lead to AHR. In conclusion, AHR is likely multifactorial in origin, reflecting the plasticity of ASM properties in the inflammatory environment of the asthmatic airway. PMID:26998246

  19. The Three A's in Asthma - Airway Smooth Muscle, Airway Remodeling & Angiogenesis.

    PubMed

    Keglowich, L F; Borger, P

    2015-01-01

    Asthma affects more than 300 million people worldwide and its prevalence is still rising. Acute asthma attacks are characterized by severe symptoms such as breathlessness, wheezing, tightness of the chest, and coughing, which may lead to hospitalization or death. Besides the acute symptoms, asthma is characterized by persistent airway inflammation and airway wall remodeling. The term airway wall remodeling summarizes the structural changes in the airway wall: epithelial cell shedding, goblet cell hyperplasia, hyperplasia and hypertrophy of the airway smooth muscle (ASM) bundles, basement membrane thickening and increased vascular density. Airway wall remodeling starts early in the pathogenesis of asthma and today it is suggested that remodeling is a prerequisite for other asthma pathologies. The beneficial effect of bronchial thermoplasty in reducing asthma symptoms, together with the increased potential of ASM cells of asthmatics to produce inflammatory and angiogenic factors, indicate that the ASM cell is a major effector cell in the pathology of asthma. In the present review we discuss the ASM cell and its role in airway wall remodeling and angiogenesis. PMID:26106455

  20. The Three A’s in Asthma – Airway Smooth Muscle, Airway Remodeling & Angiogenesis

    PubMed Central

    Keglowich, L.F; Borger, P

    2015-01-01

    Asthma affects more than 300 million people worldwide and its prevalence is still rising. Acute asthma attacks are characterized by severe symptoms such as breathlessness, wheezing, tightness of the chest, and coughing, which may lead to hospitalization or death. Besides the acute symptoms, asthma is characterized by persistent airway inflammation and airway wall remodeling. The term airway wall remodeling summarizes the structural changes in the airway wall: epithelial cell shedding, goblet cell hyperplasia, hyperplasia and hypertrophy of the airway smooth muscle (ASM) bundles, basement membrane thickening and increased vascular density. Airway wall remodeling starts early in the pathogenesis of asthma and today it is suggested that remodeling is a prerequisite for other asthma pathologies. The beneficial effect of bronchial thermoplasty in reducing asthma symptoms, together with the increased potential of ASM cells of asthmatics to produce inflammatory and angiogenic factors, indicate that the ASM cell is a major effector cell in the pathology of asthma. In the present review we discuss the ASM cell and its role in airway wall remodeling and angiogenesis. PMID:26106455

  1. c-Myc regulates proliferation and Fgf10 expression in airway smooth muscle after airway epithelial injury in mouse.

    PubMed

    Volckaert, Thomas; Campbell, Alice; De Langhe, Stijn

    2013-01-01

    During lung development, Fibroblast growth factor 10 (Fgf10), which is expressed in the distal mesenchyme and regulated by Wnt signaling, acts on the distal epithelial progenitors to maintain them and prevent them from differentiating into proximal (airway) epithelial cells. Fgf10-expressing cells in the distal mesenchyme are progenitors for parabronchial smooth muscle cells (PSMCs). After naphthalene, ozone or bleomycin-induced airway epithelial injury, surviving epithelial cells secrete Wnt7b which then activates the PSMC niche to induce Fgf10 expression. This Fgf10 secreted by the niche then acts on a subset of Clara stem cells to break quiescence, induce proliferation and initiate epithelial repair. Here we show that conditional deletion of the Wnt target gene c-Myc from the lung mesenchyme during development does not affect proper epithelial or mesenchymal differentiation. However, in the adult lung we show that after naphthalene-mediated airway epithelial injury c-Myc is important for the activation of the PSMC niche and as such induces proliferation and Fgf10 expression in PSMCs. Our data indicate that conditional deletion of c-Myc from PSMCs inhibits airway epithelial repair, whereas c-Myc ablation from Clara cells has no effect on airway epithelial regeneration. These findings may have important implications for understanding the misregulation of lung repair in asthma and COPD. PMID:23967208

  2. MicroRNA regulation of airway smooth muscle function.

    PubMed

    Sun, Maoyun; Lu, Quan

    2016-06-01

    Airway smooth muscle (ASM) controls airway narrowing and plays a pivotal role in the pathogenesis of asthma. MicroRNAs are small yet powerful gene tuners that regulate diverse cellular processes. Recent studies have demonstrated the versatile role of microRNAs in regulating multiple ASM phenotypes that are critically involved in asthma pathogenesis. These ASM phenotypes include proliferation, cell size, chemokine secretion, and contractility. Here we review microRNA-mediated regulation of ASM functions and discuss the potential of microRNAs as a novel class of therapeutic targets to improve ASM function for asthma therapy. PMID:26812790

  3. Angiogenesis is induced by airway smooth muscle strain.

    PubMed

    Hasaneen, Nadia A; Zucker, Stanley; Lin, Richard Z; Vaday, Gayle G; Panettieri, Reynold A; Foda, Hussein D

    2007-10-01

    Angiogenesis is an important feature of airway remodeling in both chronic asthma and chronic obstructive pulmonary disease (COPD). Airways in those conditions are exposed to excessive mechanical strain during periods of acute exacerbations. We recently reported that mechanical strain of human airway smooth muscle (HASM) led to an increase in their proliferation and migration. Sustained growth in airway smooth muscle in vivo requires an increase in the nutritional supply to these muscles, hence angiogenesis. In this study, we examined the hypothesis that cyclic mechanical strain of HASM produces factors promoting angiogenic events in the surrounding vascular endothelial cells. Our results show: 1) a significant increase in human lung microvascular endothelial cell (HMVEC-L) proliferation, migration, and tube formation following incubation in conditioned media (CM) from HASM cells exposed to mechanical strain; 2) mechanical strain of HASM cells induced VEGF expression and release; 3) VEGF neutralizing antibodies inhibited the proliferation, migration, and tube formations of HMVEC-L induced by the strained airway smooth muscle CM; 4) mechanical strain of HASM induced a significant increase in hypoxia-inducible factor-1alpha (HIF-1alpha) mRNA and protein, a transcription factor required for VEGF gene transcription; and 5) mechanical strain of HASM induced HIF-1alpha/VEGF through dual phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) and ERK pathways. In conclusion, exposing HASM cells to mechanical strain induces signal transduction pathway through PI3K/Akt/mTOR and ERK pathways that lead to an increase in HIF-1alpha, a transcription factor required for VEGF expression. VEGF release by mechanical strain of HASM may contribute to the angiogenesis seen with repeated exacerbation of asthma and COPD. PMID:17693481

  4. Human airway smooth muscle cells secrete amphiregulin via bradykinin/COX-2/PGE2, inducing COX-2, CXCL8, and VEGF expression in airway epithelial cells

    PubMed Central

    Knox, Alan J.

    2015-01-01

    Human airway smooth muscle cells (HASMC) contribute to asthma pathophysiology through an increased smooth muscle mass and elevated cytokine/chemokine output. Little is known about how HASMC and the airway epithelium interact to regulate chronic airway inflammation and remodeling. Amphiregulin is a member of the family of epidermal growth factor receptor (EGFR) agonists with cell growth and proinflammatory roles and increased expression in the lungs of asthma patients. Here we show that bradykinin (BK) stimulation of HASMC increases amphiregulin secretion in a mechanism dependent on BK-induced COX-2 expression, increased PGE2 output, and the stimulation of HASMC EP2 and EP4 receptors. Conditioned medium from BK treated HASMC induced CXCL8, VEGF, and COX-2 mRNA and protein accumulation in airway epithelial cells, which were blocked by anti-amphiregulin antibodies and amphiregulin siRNA, suggesting a paracrine effect of HASMC-derived amphiregulin on airway epithelial cells. Consistent with this, recombinant amphiregulin induced CXCL8, VEGF, and COX-2 in airway epithelial cells. Finally, we found that conditioned media from amphiregulin-stimulated airway epithelial cells induced amphiregulin expression in HASMC and that this was dependent on airway epithelial cell COX-2 activity. Our study provides evidence of a dynamic axis of interaction between HASMC and epithelial cells that amplifies CXCL8, VEGF, COX-2, and amphiregulin production. PMID:26047642

  5. The Pivotal Role of Airway Smooth Muscle in Asthma Pathophysiology

    PubMed Central

    Ozier, Annaïg; Allard, Benoit; Bara, Imane; Girodet, Pierre-Olivier; Trian, Thomas; Marthan, Roger; Berger, Patrick

    2011-01-01

    Asthma is characterized by the association of airway hyperresponsiveness (AHR), inflammation, and remodelling. The aim of the present article is to review the pivotal role of airway smooth muscle (ASM) in the pathophysiology of asthma. ASM is the main effector of AHR. The mechanisms of AHR in asthma may involve a larger release of contractile mediators and/or a lower release of relaxant mediators, an improved ASM cell excitation/contraction coupling, and/or an alteration in the contraction/load coupling. Beyond its contractile function, ASM is also involved in bronchial inflammation and remodelling. Whereas ASM is a target of the inflammatory process, it can also display proinflammatory and immunomodulatory functions, through its synthetic properties and the expression of a wide range of cell surface molecules. ASM remodelling represents a key feature of asthmatic bronchial remodelling. ASM also plays a role in promoting complementary airway structural alterations, in particular by its synthetic function. PMID:22220184

  6. Increase in passive stiffness at reduced airway smooth muscle length: potential impact on airway responsiveness.

    PubMed

    Bossé, Ynuk; Solomon, Dennis; Chin, Leslie Y M; Lian, Kevin; Paré, Peter D; Seow, Chun Y

    2010-03-01

    The amplitude of strain in airway smooth muscle (ASM) produced by oscillatory perturbations such as tidal breathing or deep inspiration (DI) influences the force loss in the muscle and is therefore a key determinant of the bronchoprotective and bronchodilatory effects of these breathing maneuvers. The stiffness of unstimulated ASM (passive stiffness) directly influences the amplitude of strain. The nature of the passive stiffness is, however, not clear. In this study, we measured the passive stiffness of ovine ASM at different muscle lengths (relative to in situ length, which was used as a reference length, L(ref)) and states of adaptation to gain insights into the origin of this muscle property. The results showed that the passive stiffness was relatively independent of muscle length, possessing a constant plateau value over a length range from 0.62 to 1.25 L(ref). Following a halving of ASM length, passive stiffness decreased substantially (by 71%) but redeveloped over time ( approximately 30 min) at the shorter length to reach 65% of the stiffness value at L(ref), provided that the muscle was stimulated to contract at least once over a approximately 30-min period. The redevelopment and maintenance of passive stiffness were dependent on the presence of Ca(2+) but unaffected by latrunculin B, an inhibitor of actin filament polymerization. The maintenance of passive stiffness was also not affected by blocking myosin cross-bridge cycling using a myosin light chain kinase inhibitor or by blocking the Rho-Rho kinase (RhoK) pathway using a RhoK inhibitor. Our results suggest that the passive stiffness of ASM is labile and capable of redevelopment following length reduction. Redevelopment and maintenance of passive stiffness following muscle shortening could contribute to airway hyperresponsiveness by attenuating the airway wall strain induced by tidal breathing and DI. PMID:20008114

  7. Airway smooth muscle growth from the perspective of animal models.

    PubMed

    Martin, James G; Ramos-Barbón, David

    2003-09-16

    Airway smooth muscle maintains airway tone and may assist in adjusting ventilation distribution within the normal lung. Alterations in the properties or the quantity of ASM are likely responsible for some instances of airways hyperresponsiveness to bronchoconstrictive stimuli that is a characteristic of diseases such as asthma. Morphometric studies have shown an increase in the mass of ASM in human asthmatic airways. Animal models have been developed that confirm that ASM can be induced to grow by allergic sensitization and challenge. Growth is in large part by hyperplasia as measured by incorporation of bromodeoxyuridine as a marker of the S-phase of the cell cycle. T cells, in particular CD4+ cells, may participate in the stimulation of growth of ASM by allergen challenge. The growth factors responsible for the increase in ASM are as yet unidentified but two mediators associated with allergic airway responses, cysteinyl leukotrienes and endothelin, have been implicated using specific receptor antagonists. The links between T cells and the biochemical mediators of growth have not been established. PMID:14516730

  8. Cigarette smoke enhances proliferation and extracellular matrix deposition by human fetal airway smooth muscle

    PubMed Central

    Vogel, Elizabeth R.; VanOosten, Sarah K.; Holman, Michelle A.; Hohbein, Danielle D.; Thompson, Michael A.; Vassallo, Robert; Pandya, Hitesh C.; Prakash, Y. S.

    2014-01-01

    Cigarette smoke is a common environmental insult associated with increased risk of developing airway diseases such as wheezing and asthma in neonates and children. In adults, asthma involves airway remodeling characterized by increased airway smooth muscle (ASM) cell proliferation and increased extracellular matrix (ECM) deposition, as well as airway hyperreactivity. The effects of cigarette smoke on remodeling and contractility in the developing airway are not well-elucidated. In this study, we used canalicular-stage (18–20 wk gestational age) human fetal airway smooth muscle (fASM) cells as an in vitro model of the immature airway. fASM cells were exposed to cigarette smoke extract (CSE; 0.5–1.5% for 24–72 h), and cell proliferation, ECM deposition, and intracellular calcium ([Ca2+]i) responses to agonist (histamine 10 μM) were used to evaluate effects on remodeling and hyperreactivity. CSE significantly increased cell proliferation and deposition of ECM molecules collagen I, collagen III, and fibronectin. In contrast, [Ca2+]i responses were not significantly affected by CSE. Analysis of key signaling pathways demonstrated significant increase in extracellular signal-related kinase (ERK) and p38 activation with CSE. Inhibition of ERK or p38 signaling prevented CSE-mediated changes in proliferation, whereas only ERK inhibition attenuated the CSE-mediated increase in ECM deposition. Overall, these results demonstrate that cigarette smoke may enhance remodeling in developing human ASM through hyperplasia and ECM production, thus contributing to development of neonatal and pediatric airway disease. PMID:25344066

  9. Does the length dependency of airway smooth muscle force contribute to airway hyperresponsiveness?

    PubMed

    Lee-Gosselin, Audrey; Pascoe, Chris D; Couture, Christian; Paré, Peter D; Bossé, Ynuk

    2013-11-01

    Airway wall remodeling and lung hyperinflation are two typical features of asthma that may alter the contractility of airway smooth muscle (ASM) by affecting its operating length. The aims of this study were as follows: 1) to describe in detail the "length dependency of ASM force" in response to different spasmogens; and 2) to predict, based on morphological data and a computational model, the consequence of this length dependency of ASM force on airway responsiveness in asthmatic subjects who have both remodeled airway walls and hyperinflated lungs. Ovine tracheal ASM strips and human bronchial rings were isolated and stimulated to contract in response to increasing concentrations of spasmogens at three different lengths. Ovine tracheal strips were more sensitive and generated greater force at longer lengths in response to acetylcholine (ACh) and K(+). Equipotent concentrations of ACh were approximately a log less for ASM stretched by 30% and approximately a log more for ASM shortened by 30%. Similar results were observed in human bronchi in response to methacholine. Morphometric and computational analyses predicted that the ASM of asthmatic subjects may be elongated by 6.6-10.4% (depending on airway generation) due to remodeling and/or hyperinflation, which could increase ACh-induced force by 1.8-117.8% (depending on ASM length and ACh concentration) and enhance the increased resistance to airflow by 0.4-4,432.8%. In conclusion, elongation of ASM imposed by airway wall remodeling and/or hyperinflation may allow ASM to operate at a longer length and to consequently generate more force and respond to lower concentration of spasmogens. This phenomenon could contribute to airway hyperresponsiveness. PMID:23970527

  10. Histochemical properties of upper airway muscles: comparison of dilator and nondilator muscles.

    PubMed

    Bracher, A; Coleman, R; Schnall, R; Oliven, A

    1997-05-01

    The upper airway dilator muscles (UADMs) represent a subgroup of muscles in the pharyngeal area which, in addition to their roles in mastication, vocalization, etc., also have an important respiratory function. Failure of these muscles to maintain upper airway patency during sleep is important in the development of the obstructive sleep apnoea syndrome. In the present study, we evaluated the histochemical properties of the UADMs and compared them to those of neighbouring muscles without respiratory functions, and to the diaphragm, to determine whether the UADMs are specifically adapted to their respiratory role. Our results, both in dogs and rats, indicate that the dilator and nondilator upper airway muscles are similar and differ from the diaphragm. In rats, there were significantly less type I fibres (<12% as compared to 42% for the diaphragm) and more type IIb fibres (39-67% as compared to 27% for the diaphragm). A similar pattern was seen in dogs: type I fibres <38% as compared to 46% for the diaphragm, and type IIb fibres, 29-35% as compared to 10% for the diaphragm. These findings suggest that the upper airway dilator muscles are not specifically designed for their respiratory role. They may fail in the presence of increased loads, often encountered in patients with obstructive sleep apnoea, unless appropriate adaptive structural changes take place. PMID:9163636

  11. Airway compliance and dynamics explain the apparent discrepancy in length adaptation between intact airways and smooth muscle strips.

    PubMed

    Dowie, Jackson; Ansell, Thomas K; Noble, Peter B; Donovan, Graham M

    2016-01-01

    Length adaptation is a phenomenon observed in airway smooth muscle (ASM) wherein over time there is a shift in the length-tension curve. There is potential for length adaptation to play an important role in airway constriction and airway hyper-responsiveness in asthma. Recent results by Ansell et al., 2015 (JAP 2014 10.1152/japplphysiol.00724.2014) have cast doubt on this role by testing for length adaptation using an intact airway preparation, rather than strips of ASM. Using this technique they found no evidence for length adaptation in intact airways. Here we attempt to resolve this apparent discrepancy by constructing a minimal mathematical model of the intact airway, including ASM which follows the classic length-tension curve and undergoes length adaptation. This allows us to show that (1) no evidence of length adaptation should be expected in large, cartilaginous, intact airways; (2) even in highly compliant peripheral airways, or at more compliant regions of the pressure-volume curve of large airways, the effect of length adaptation would be modest and at best marginally detectable in intact airways; (3) the key parameters which control the appearance of length adaptation in intact airways are airway compliance and the relaxation timescale. The results of this mathematical simulation suggest that length adaptation observed at the level of the isolated ASM may not clearly manifest in the normal intact airway. PMID:26376002

  12. Bitter tasting compounds dilate airways by inhibiting airway smooth muscle calcium oscillations and calcium sensitivity

    PubMed Central

    Tan, Xiahui; Sanderson, Michael J

    2014-01-01

    Background and Purpose While selective, bitter tasting, TAS2R agonists can relax agonist-contracted airway smooth muscle (ASM), their mechanism of action is unclear. However, ASM contraction is regulated by Ca2+ signalling and Ca2+ sensitivity. We have therefore investigated how the TAS2R10 agonists chloroquine, quinine and denotonium regulate contractile agonist-induced Ca2+ signalling and sensitivity. Experimental Approach Airways in mouse lung slices were contracted with either methacholine (MCh) or 5HT and bronchodilation assessed using phase-contrast microscopy. Ca2+ signalling was measured with 2-photon fluorescence microscopy of ASM cells loaded with Oregon Green, a Ca2+-sensitive indicator (with or without caged-IP3). Effects on Ca2+ sensitivity were assessed on lung slices treated with caffeine and ryanodine to permeabilize ASM cells to Ca2+. Key Results The TAS2R10 agonists dilated airways constricted by either MCh or 5HT, accompanied by inhibition of agonist-induced Ca2+ oscillations. However, in non-contracted airways, TAS2R10 agonists, at concentrations that maximally dilated constricted airways, did not evoke Ca2+ signals in ASM cells. Ca2+ increases mediated by the photolysis of caged-IP3 were also attenuated by chloroquine, quinine and denotonium. In Ca2+-permeabilized ASM cells, the TAS2R10 agonists dilated MCh- and 5HT-constricted airways. Conclusions and Implications TAS2R10 agonists reversed bronchoconstriction by inhibiting agonist-induced Ca2+ oscillations while simultaneously reducing the Ca2+ sensitivity of ASM cells. Reduction of Ca2+ oscillations may be due to inhibition of Ca2+ release through IP3 receptors. Further characterization of bronchodilatory TAS2R agonists may lead to the development of novel therapies for the treatment of bronchoconstrictive conditions. PMID:24117140

  13. Peripheral Airway Smooth Muscle, but Not the Trachealis, Is Hypercontractile in an Equine Model of Asthma.

    PubMed

    Matusovsky, Oleg S; Kachmar, Linda; Ijpma, Gijs; Bates, Genevieve; Zitouni, Nedjma; Benedetti, Andrea; Lavoie, Jean-Pierre; Lauzon, Anne-Marie

    2016-05-01

    Heaves is a naturally occurring equine disease that shares many similarities with human asthma, including reversible antigen-induced bronchoconstriction, airway inflammation, and remodeling. The purpose of this study was to determine whether the trachealis muscle is mechanically representative of the peripheral airway smooth muscle (ASM) in an equine model of asthma. Tracheal and peripheral ASM of heaves-affected horses under exacerbation, or under clinical remission of the disease, and control horses were dissected and freed of epithelium to measure unloaded shortening velocity (Vmax), stress (force/cross-sectional area), methacholine effective concentration at which 50% of the maximum response is obtained, and stiffness. Myofibrillar Mg(2+)-ATPase activity, actomyosin in vitro motility, and contractile protein expression were also measured. Horses with heaves had significantly greater Vmax and Mg(2+)-ATPase activity in peripheral airway but not in tracheal smooth muscle. In addition, a significant correlation was found between Vmax and the time elapsed since the end of the corticosteroid treatment for the peripheral airways in horses with heaves. Maximal stress and stiffness were greater in the peripheral airways of the horses under remission compared with controls and the horses under exacerbation, potentially due to remodeling. Actomyosin in vitro motility was not different between controls and horses with heaves. These data demonstrate that peripheral ASM is mechanically and biochemically altered in heaves, whereas the trachealis behaves as in control horses. It is therefore conceivable that the trachealis muscle may not be representative of the peripheral ASM in human asthma either, but this will require further investigation. PMID:26473389

  14. Large conducting potassium channel reconstituted from airway smooth muscle.

    PubMed

    Savaria, D; Lanoue, C; Cadieux, A; Rousseau, E

    1992-03-01

    Microsomal fractions were prepared from canine and bovine airway smooth muscle (ASM) by differential and gradient centrifugations. Surface membrane vesicles were characterized by binding assays and incorporated into planar lipid bilayers. Single-channel activities were recorded in symmetric or asymmetric K+ buffer systems and studied under voltage and Ca2+ clamp conditions. A large-conductance K(+)-selective channel (greater than 220 pS in 150 mM K+) displaying a high Ca2+, low Ba2+, and charybdotoxin (CTX) sensitivity was identified. Time analysis of single-channel recordings revealed a complex kinetic behavior compatible with the previous schemes proposed for Ca(2+)-activated K+ channels in a variety of biological surface membranes. We now report that the open probability of the channel at low Ca2+ concentration is enhanced on in vitro phosphorylation, which is mediated via an adenosine 3',5'-cyclic monophosphate-dependent protein kinase. In addition to this characterization at the molecular level, a second series of pharmacological experiments were designed to assess the putative role of this channel in ASM strips. Our results show that 50 nM CTX, a specific inhibitor of the large conducting Ca(2+)-dependent K+ channel, prevents norepinephrine transient relaxation on carbamylcholine-precontracted ASM strips. It was also shown that CTX reversed the steady-state relaxation induced by vasoactive intestinal peptide and partially antagonized further relaxation induced by cumulative doses of this potent bronchodilatator. Thus it is proposed that the Ca(2+)-activated K+ channels have a physiological role because they are indirectly activated on stimulation of various membrane receptors via intracellular mechanisms. PMID:1372487

  15. Effect of gender on rat upper airway muscle contractile properties.

    PubMed

    Cantillon, D; Bradford, A

    1998-08-01

    Obstructive sleep apnoea arises due to upper airway (UA) collapse which is normally counteracted by contraction of UA muscles such as the sternohyoids and geniohyoids. The disorder has a marked male predominance but the effect of gender on UA muscle contractile properties is unknown and these properties have not been compared for the sternohyoid and geniohyoid muscles in the same species. Isometric contractile characteristics were determined using strips of sternohyoid and geniohyoid muscle from male and female rats in Krebs solution at 30 degrees C. For both muscles, there were no differences between male and female contractile kinetics, twitch or tetanic tension, tension-length or tension-frequency relationship or endurance. In both males and females, sternohyoid twitch and tetanic tension was greater than geniohyoid. Sternohyoid endurance was less than geniohyoid but contractile kinetics, tension-length and tension-frequency relationships were similar. Therefore, gender does not affect UA muscle contractile properties and sternohyoid tension is greater and endurance less than that of the geniohyoid. PMID:9832233

  16. Steroids augment relengthening of contracted airway smooth muscle: potential additional mechanism of benefit in asthma.

    PubMed

    Lakser, O J; Dowell, M L; Hoyte, F L; Chen, B; Lavoie, T L; Ferreira, C; Pinto, L H; Dulin, N O; Kogut, P; Churchill, J; Mitchell, R W; Solway, J

    2008-11-01

    Breathing (especially deep breathing) antagonises development and persistence of airflow obstruction during bronchoconstrictor stimulation. Force fluctuations imposed on contracted airway smooth muscle (ASM) in vitro result in its relengthening, a phenomenon called force fluctuation-induced relengthening (FFIR). Because breathing imposes similar force fluctuations on contracted ASM within intact lungs, FFIR represents a likely mechanism by which breathing antagonises bronchoconstriction. While this bronchoprotective effect appears to be impaired in asthma, corticosteroid treatment can restore the ability of deep breaths to reverse artificially induced bronchoconstriction in asthmatic subjects. It has previously been demonstrated that FFIR is physiologically regulated through the p38 mitogen-activated protein kinase (MAPK) signalling pathway. While the beneficial effects of corticosteroids have been attributed to suppression of airway inflammation, the current authors hypothesised that alternatively they might exert their action directly on ASM by augmenting FFIR as a result of inhibiting p38 MAPK signalling. This possibility was tested in the present study by measuring relengthening in contracted canine tracheal smooth muscle (TSM) strips. The results indicate that dexamethasone treatment significantly augmented FFIR of contracted canine TSM. Canine tracheal ASM cells treated with dexamethasone demonstrated increased MAPK phosphatase-1 expression and decreased p38 MAPK activity, as reflected in reduced phosphorylation of the p38 MAPK downstream target, heat shock protein 27. These results suggest that corticosteroids may exert part of their therapeutic effect through direct action on airway smooth muscle, by decreasing p38 mitogen-activated protein kinase activity and thus increasing force fluctuation-induced relengthening. PMID:18768574

  17. Orai channel-mediated Ca2+ signals in vascular and airway smooth muscle.

    PubMed

    Spinelli, Amy M; Trebak, Mohamed

    2016-03-15

    Orai (Orai1, Orai2, and Orai3) proteins form a family of highly Ca(2+)-selective plasma membrane channels that are regulated by stromal-interacting molecules (STIM1 and STIM2); STIM proteins are Ca(2+) sensors located in the membrane of the endoplasmic reticulum. STIM and Orai proteins are expressed in vascular and airway smooth muscle and constitute the molecular components of the ubiquitous store-operated Ca(2+) entry pathway that mediate the Ca(2+) release-activated Ca(2+) current. STIM/Orai proteins also encode store-independent Ca(2+) entry pathways in smooth muscle. Altered expression and function of STIM/Orai proteins have been linked to vascular and airway pathologies, including restenosis, hypertension, and atopic asthma. In this review we discuss our current understanding of Orai proteins and the store-dependent and -independent signaling pathways mediated by these proteins in vascular and airway smooth muscle. We also discuss the current studies linking altered expression and function of Orai proteins with smooth muscle-related pathologies. PMID:26718630

  18. Airway smooth muscle and bronchospasm: fluctuating, fluidizing, freezing

    PubMed Central

    Krishnan, Ramaswamy; Trepat, Xavier; Nguyen, Trang T. B.; Lenormand, Guillaume; Oliver, Madavi; Fredberg, Jeffrey J.

    2008-01-01

    We review here four recent findings that have altered in a fundamental way our understanding of airways smooth muscle (ASM), its dynamic responses to physiological loading, and their dominant mechanical role in bronchospasm. These findings highlight ASM remodeling processes that are innately out-of-equilibrium and dynamic, and bring to the forefront a striking intersection between topics in condensed matter physics and ASM cytoskeletal biology. By doing so, they place in a new light the role of enhanced ASM mass in airway hyper-responsiveness as well as in the failure of a deep inspiration to relax the asthmatic airway. These findings have established that (i) ASM length is equilibrated dynamically, not statically; (ii) ASM dynamics closely resemble physical features exhibited by so-called soft glassy materials; (iii) static force-length relationships fail to describe dynamically contracted ASM states; (iv) stretch fluidizes the ASM cytoskeleton. Taken together, these observations suggest that at the origin of the bronchodilatory effect of a deep inspiration, and its failure in asthma, may lie glassy dynamics of the ASM cell. PMID:18514592

  19. Matrix stiffness-modulated proliferation and secretory function of the airway smooth muscle cells.

    PubMed

    Shkumatov, Artem; Thompson, Michael; Choi, Kyoung M; Sicard, Delphine; Baek, Kwanghyun; Kim, Dong Hyun; Tschumperlin, Daniel J; Prakash, Y S; Kong, Hyunjoon

    2015-06-01

    Multiple pulmonary conditions are characterized by an abnormal misbalance between various tissue components, for example, an increase in the fibrous connective tissue and loss/increase in extracellular matrix proteins (ECM). Such tissue remodeling may adversely impact physiological function of airway smooth muscle cells (ASMCs) responsible for contraction of airways and release of a variety of bioactive molecules. However, few efforts have been made to understand the potentially significant impact of tissue remodeling on ASMCs. Therefore, this study reports how ASMCs respond to a change in mechanical stiffness of a matrix, to which ASMCs adhere because mechanical stiffness of the remodeled airways is often different from the physiological stiffness. Accordingly, using atomic force microscopy (AFM) measurements, we found that the elastic modulus of the mouse bronchus has an arithmetic mean of 23.1 ± 14 kPa (SD) (median 18.6 kPa). By culturing ASMCs on collagen-conjugated polyacrylamide hydrogels with controlled elastic moduli, we found that gels designed to be softer than average airway tissue significantly increased cellular secretion of vascular endothelial growth factor (VEGF). Conversely, gels stiffer than average airways stimulated cell proliferation, while reducing VEGF secretion and agonist-induced calcium responses of ASMCs. These dependencies of cellular activities on elastic modulus of the gel were correlated with changes in the expression of integrin-β1 and integrin-linked kinase (ILK). Overall, the results of this study demonstrate that changes in matrix mechanics alter cell proliferation, calcium signaling, and proangiogenic functions in ASMCs. PMID:25724668

  20. Smooth muscle in human bronchi is disposed to resist airway distension.

    PubMed

    Gazzola, Morgan; Henry, Cyndi; Couture, Christian; Marsolais, David; King, Gregory G; Fredberg, Jeffrey J; Bossé, Ynuk

    2016-07-15

    Studying airway smooth muscle (ASM) in conditions that emulate the in vivo environment within which the bronchi normally operate may provide important clues regarding its elusive physiological function. The present study examines the effect of lengthening and shortening of ASM on tension development in human bronchial segments. ASM from each bronchial segment was set at a length approximating in situ length (Linsitu). Bronchial tension was then measured during a slow cyclical strain (0.004Hz, from 0.7Linsitu to 1.3Linsitu) in the relaxed state and at graded levels of activation by methacholine. In all cases, tension was greater at longer ASM lengths, and greater during lengthening than shortening. The threshold of methacholine concentration that was required for ASM to account for bronchial tension across the entire range of ASM lengths tested was on average smaller by 2.8 logs during lengthening than during shortening. The length-dependency of ASM tension, together with this lower threshold of methacholine concentration during lengthening versus shortening, suggest that ASM has a greater ability to resist airway dilation during lung inflation than to narrow the airways during lung deflation. More than serving to narrow the airway, as has long been thought, these data suggest that the main function of ASM contraction is to limit airway wall distension during lung inflation. PMID:27095271

  1. Kinematic MRI study of upper-airway biomechanics using electrical muscle stimulation

    NASA Astrophysics Data System (ADS)

    Brennick, Michael J.; Margulies, Susan S.; Ford, John C.; Gefter, Warren B.; Pack, Allan I.

    1997-05-01

    We have developed a new and powerful method to study the movement and function of upper airway muscles. Our method is to use direct electrical stimulation of individual upper airway muscles, while performing state of the art high resolution magnetic resonance imaging (MRI). We have adapted a paralyzed isolated UA cat model so that positive or negative static pressure in the UA can be controlled at specific levels while electrical muscle stimulation is applied during MRI. With these techniques we can assess the effect of muscle stimulation on airway cross-sectional area compliance and soft tissue motion. We are reporting the preliminary results and MRI techniques which have enabled us to examine changes in airway dimensions which result form electrical stimulation of specific upper airway dilator muscles. The results of this study will be relevant to the development of new clinical treatments for obstructive sleep apnea by providing new information as to exactly how upper airway muscles function to dilate the upper airway and the strength of stimulation required to prevent the airway obstruction when overall muscle tone may not be sufficient to maintain regular breathing.

  2. IL-1β: a key modulator in asthmatic airway smooth muscle hyper-reactivity.

    PubMed

    Liao, Zhi; Xiao, Hong-tao; Zhang, Yuan; Tong, Rong-Sheng; Zhang, Li-Juan; Bian, Yuan; He, Xia

    2015-08-01

    Asthma is a chronic inflammatory disorder of the airway. It is characterized by airway hyper-reactivity, which can be attributed to the chronically inflamed airway. However, the molecular mechanism is still under investigation. In this article, we have shown that IL-1β is a key molecule that can orchestrate both Toll-like receptor and muscarinic receptor pathways, and that antagonizing the function of IL-1β has a promising future as a potential drug target for asthma treatment. IL-1β can activate NF-κB pathways via Toll-like receptors, and NF-κB will eventually transactivate the genes of cytokines, chemokines, proteins of the complement system, adhesion molecules and immune receptors involved in inflammation. IL-1β can activate eosinophils, which can release major basic protein (MBP) to antagonize the M2 receptors leading to excessive acetylcholine release. Acetylcholine has an effect on M3 receptors, which are related to airway smooth muscle contraction and mucus production. IL-1β is reported to activate COX-2 resulting in heterologous desensitization of adenylate cyclase and impairs relaxation of the ASM. IL-1β is involved in mediation of neutrophilic inflammation. Identification of the prominent role of IL-1β in asthma could lead to successful use of anti-IL1β agents. PMID:26134749

  3. Antimitogenic effect of bitter taste receptor agonists on airway smooth muscle cells.

    PubMed

    Sharma, Pawan; Panebra, Alfredo; Pera, Tonio; Tiegs, Brian C; Hershfeld, Alena; Kenyon, Lawrence C; Deshpande, Deepak A

    2016-02-15

    Airway remodeling is a hallmark feature of asthma and chronic obstructive pulmonary disease. Clinical studies and animal models have demonstrated increased airway smooth muscle (ASM) mass, and ASM thickness is correlated with severity of the disease. Current medications control inflammation and reverse airway obstruction effectively but have limited effect on remodeling. Recently we identified the expression of bitter taste receptors (TAS2R) on ASM cells, and activation with known TAS2R agonists resulted in ASM relaxation and bronchodilation. These studies suggest that TAS2R can be used as new therapeutic targets in the treatment of obstructive lung diseases. To further establish their effectiveness, in this study we aimed to determine the effects of TAS2R agonists on ASM growth and promitogenic signaling. Pretreatment of healthy and asthmatic human ASM cells with TAS2R agonists resulted in a dose-dependent inhibition of ASM proliferation. The antimitogenic effect of TAS2R ligands was not dependent on activation of protein kinase A, protein kinase C, or high/intermediate-conductance calcium-activated K(+) channels. Immunoblot analyses revealed that TAS2R agonists inhibit growth factor-activated protein kinase B phosphorylation without affecting the availability of phosphatidylinositol 3,4,5-trisphosphate, suggesting TAS2R agonists block signaling downstream of phosphatidylinositol 3-kinase. Furthermore, the antimitogenic effect of TAS2R agonists involved inhibition of induced transcription factors (activator protein-1, signal transducer and activator of transcription-3, E2 factor, nuclear factor of activated T cells) and inhibition of expression of multiple cell cycle regulatory genes, suggesting a direct inhibition of cell cycle progression. Collectively, these findings establish the antimitogenic effect of TAS2R agonists and identify a novel class of receptors and signaling pathways that can be targeted to reduce or prevent airway remodeling as well as

  4. Regulation of actin dynamics by WNT-5A: implications for human airway smooth muscle contraction

    PubMed Central

    Koopmans, Tim; Kumawat, Kuldeep; Halayko, Andrew J; Gosens, Reinoud

    2016-01-01

    A defining feature of asthma is airway hyperresponsiveness (AHR), which underlies the exaggerated bronchoconstriction response of asthmatics. The role of the airway smooth muscle (ASM) in AHR has garnered increasing interest over the years, but how asthmatic ASM differs from healthy ASM is still an active topic of debate. WNT-5A is increasingly expressed in asthmatic ASM and has been linked with Th2-high asthma. Due to its link with calcium and cytoskeletal remodelling, we propose that WNT-5A may modulate ASM contractility. We demonstrated that WNT-5A can increase maximum isometric tension in bovine tracheal smooth muscle strips. In addition, we show that WNT-5A is preferentially expressed in contractile human airway myocytes compared to proliferative cells, suggesting an active role in maintaining contractility. Furthermore, WNT-5A treatment drives actin polymerisation, but has no effect on intracellular calcium flux. Next, we demonstrated that WNT-5A directly regulates TGF-β1-induced expression of α-SMA via ROCK-mediated actin polymerization. These findings suggest that WNT-5A modulates fundamental mechanisms that affect ASM contraction and thus may be of relevance for AHR in asthma. PMID:27468699

  5. Differential Expression of Lipid and Carbohydrate Metabolism Genes in Upper Airway versus Diaphragm Muscle

    PubMed Central

    van Lunteren, Erik; Spiegler, Sarah; Moyer, Michelle

    2010-01-01

    Study Objectives: Contractile properties of upper airway muscles influence upper airway patency, an issue of particular importance for subjects with obstructive sleep apnea. Expression of genes related to cellular energetics is, in turn, critical for the maintenance of contractile integrity over time during repetitive activation. We tested the hypothesis that sternohyoid has lower expression of genes related to lipid and carbohydrate energetic pathways than the diaphragm. Methods: Sternohyoid and diaphragm from normal adult rats were examined with gene expression arrays. Analysis focused on genes belonging to Gene Ontology (GO) groups carbohydrate metabolism and lipid metabolism. Results: There were 433 genes with at least ± 2-fold significant differential expression between sternohyoid and diaphragm, of which 192 had sternohyoid > diaphragm and 241 had diaphragm > sternohyoid expression. Among genes with higher sternohyoid expression, there was over-representation of the GO group carbohydrate metabolism (P = 0.0053, n = 13 genes, range of differential expression 2.1- to 6.2-fold) but not lipid metabolism (P = 0.44). Conversely, among genes with higher diaphragm expression, there was over-representation of the GO group lipid metabolism (P = 0.0000065, n = 32 genes, range of differential expression 2.0- to 37.9-fold) but not carbohydrate metabolism (P = 0.23). Nineteen genes with diaphragm > sternohyoid expression were related to fatty acid metabolism (P = 0.000000058), in particular fatty acid β oxidation and biosynthesis in the mitochondria. Conclusions: Sternohyoid has much lower gene expression than diaphragm for mitochondrial enzymes that participate in fatty acid oxidation and biosynthesis. This likely contributes to the lower fatigue resistance of pharyngeal upper airway muscles compared with the diaphragm. Citation: van Lunteren E; Spiegler S; Moyer M. Differential expression of lipid and carbohydrate metabolism genes in upper airway versus diaphragm

  6. HB-EGF-Promoted Airway Smooth Muscle Cells and Their Progenitor Migration Contribute to Airway Smooth Muscle Remodeling in Asthmatic Mouse.

    PubMed

    Wang, Qing; Li, Hequan; Yao, Yinan; Lu, Guohua; Wang, Yuehong; Xia, Dajing; Zhou, Jianying

    2016-03-01

    The airway smooth muscle (ASM) cells' proliferation, migration, and their progenitor's migration are currently regarded as causative factors for ASM remodeling in asthma. Heparin-binding epidermal growth factor (HB-EGF), a potent mitogen and chemotactic factor, could promote ASM cell proliferation through MAPK pathways. In this study, we obtained primary ASM cells and their progenitors from C57BL/6 mice and went on to explore the role of HB-EGF in these cells migration and the underlying mechanisms. We found that recombinant HB-EGF (rHB-EGF) intratracheal instillation accelerated ASM layer thickening in an OVA-induced asthmatic mouse. Modified Boyden chamber assay revealed that rHB-EGF facilitate ASM cell migration in a dose-dependent manner and ASM cells from asthmatic mice had a greater migration ability than that from normal counterparts. rHB-EGF could stimulate the phosphorylation of ERK1/2 and p38 in ASM cells but further migration assay showed that only epidermal growth factor receptor inhibitor (AG1478) or p38 inhibitor (SB203580), but not ERK1/2 inhibitor (PD98059), could inhibit rHB-EGF-mediated ASM cells migration. Actin cytoskeleton experiments exhibited that rHB-EGF could cause actin stress fibers disassembly and focal adhesions formation of ASM cells through the activation of p38. Finally, airway instillation of rHB-EGF promoted the recruitment of bone marrow-derived smooth muscle progenitor cells, which were transferred via caudal vein, migrating into the airway from the circulation. These observations demonstrated that ASM remodeling in asthma might have resulted from HB-EGF-mediated ASM cells and their progenitor cells migration, via p38 MAPK-dependent actin cytoskeleton remodeling. PMID:26826248

  7. Effect of inflammatory mediators on airway nerves and muscle

    SciTech Connect

    Daniel, E.E.; O'Byrne, P. )

    1991-03-01

    The neuromuscular mechanisms underlying airway hyperresponsiveness have been reviewed on the basis of studies of the changes induced by ozone inhalation in dogs. In vivo, there is increased, nonspecific airway hyperresponsiveness based on studies of the response to inhaled acetylcholine or histamine. The underlying inflammatory mechanism involves release of LTB4 and/or other chemotactic agents from epithelial or lumenal cells, ingress of macrophages, neutrophils, and platelets from the blood vessels between the muscle and epithelium, and migration of mast cells into the epithelium. The hyperresponsiveness seems to depend upon the influx of neutrophils and actions of thromboxane A2 released from the neutrophils. In vitro, there is increased responsiveness to field stimulation of cholinergic nerves and to acetylcholine (not to KCI) in tracheal strips. These effects can be mimicked by a thromboxane A2 analog (U44619). In the sucrose gap, the TxA2 analog does not affect the excitatory junction potential, but in low concentration it increases and prolongs a series of fading membrane oscillations closely related to the contractions. We consider these oscillations to reflect ongoing release and/or action of acetylcholine. In high concentrations the analog causes a small depolarization and a tonic contraction, but it does not enhance the sensitivity to acetylcholine. TxA2 may be acting either presynaptically or postsynaptically or both to produce these effects; however, changes in release of an epithelial-derived relaxing factor do not seem to be involved. We conclude that TxA2 actions probably underlie hyperresponsiveness developed in vivo and in vitro after ozone inhalation.

  8. Inflammatory responses of airway smooth muscle cells and effects of endothelin receptor antagonism.

    PubMed

    Knobloch, Jürgen; Lin, Yingfeng; Konradi, Jürgen; Jungck, David; Behr, Juergen; Strauch, Justus; Stoelben, Erich; Koch, Andrea

    2013-07-01

    Endothelin receptor antagonists (ETRAs), authorized for pulmonary hypertension, have failed to prove their utility in chronic lung diseases with corticosteroid-resistant airway inflammation when applied at late disease stages with emphysema/fibrosis. Earlier administration might prove effective by targeting the interaction between airway inflammation and tissue remodeling. We hypothesized that human airway smooth muscle cells (HASMCs) participate in linking inflammation with remodeling and that associated genes become differentially suppressed by ambrisentan (A-receptor selective ETRA) and bosentan (nonselective/dual ETRA). Inflammatory responses of ex vivo-cultivated HASMCs to TNF-α were investigated by whole-genome microarray analyses. qRT-PCR and ELISA were used to test inflammatory and remodeling genes for sensitivity to bosentan and ambrisentan and to investigate differential sensitivities mechanistically. ETRA and corticosteroid effects were compared in HASMCs from patients with chronic obstructive pulmonary disease. TNF-α induced the expression of 18 cytokines/chemokines and five tissue remodeling genes involved in severe, corticosteroid-insensitive asthma, chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, and/or pulmonary hypertension. Thirteen cytokines/chemokines, MMP13, and WISP1 were suppressed by ETRAs. Eight genes had differential sensitivity to bosentan and ambrisentan depending on the endothelin-B receptor impact on transcriptional regulation and mRNA stabilization. Chemokine (C-C motif) ligands 2 and 5, granulocyte macrophage colony-stimulating factor, and MMP13 had increased sensitivity to bosentan or bosentan/dexamethasone combination versus dexamethasone alone. Suppression of cytokine and remodeling gene expression by ETRAs was confirmed in TNF-α-activated human bronchial epithelial cells. HASMCs and human bronchial epithelial cells participate in the interaction of inflammation and tissue remodeling. This interaction is

  9. Platelet-derived-growth-factor stimulation of the p42/p44 mitogen-activated protein kinase pathway in airway smooth muscle: role of pertussis-toxin-sensitive G-proteins, c-Src tyrosine kinases and phosphoinositide 3-kinase.

    PubMed Central

    Conway, A M; Rakhit, S; Pyne, S; Pyne, N J

    1999-01-01

    The mechanism used by the platelet-derived growth factor receptor (PDGFR) to activate the mitogen-activated- protein-kinase (p42/p44 MAPK) pathway was investigated in cultured airway smooth muscle (ASM) cells. We have found that pertussis toxin (PTX, which was used to inactivate the heterotrimeric G-protein Gi) induced an approx. 40-50% decrease in the activation of c-Src and p42/p44 MAPK by PDGF. An essential role for c-Src was confirmed using the c-Src inhibitor, PP1, which abolished p42/p44 MAPK activation (PP1 and PTX were without effect on PDGFR tyrosine phosphorylation). Furthermore, the PTX-dependent decrease in c-Src and p42/p44 MAPK activation appeared correlated. These findings suggest that the PDGFR can utilize the PTX-sensitive G-protein, Gi, to regulate c-Src and subsequent p42/p44 MAPK activation. Phosphoinositide 3-kinase (PI3K) has been shown by others to be involved in p42/p44 MAPK activation. This is confirmed here by experiments which showed that PI3K inhibitors (wortmannin and LY294002) reduced the activation of p42/p44 MAPK by PDGF. PI3K activity was increased in Grb-2 immunoprecipitates from PDGF-stimulated cells and was decreased by pretreating these cells with PTX. These findings show that Gi might also promote Grb-2-PI3K complex formation and that Grb-2 may be a site at which PI3K is integrated into the p42/p44 MAPK cascade. In conclusion, our results demonstrate that Gi enables the PDGFR to signal more efficiently to p42/p44 MAPK, and this appears to be achieved through the regulation of c-Src and Grb-2/PI3K, which are intermediates in the p42/p44 MAPK cascade. PMID:9882612

  10. Sphingosine 1-phosphate stimulation of the p42/p44 mitogen-activated protein kinase pathway in airway smooth muscle. Role of endothelial differentiation gene 1, c-Src tyrosine kinase and phosphoinositide 3-kinase.

    PubMed Central

    Rakhit, S; Conway, A M; Tate, R; Bower, T; Pyne, N J; Pyne, S

    1999-01-01

    We report here that cultured airway smooth muscle cells contain transcripts of endothelial differentiation gene 1 (EDG-1), a prototypical orphan Gi-coupled receptor whose natural ligand is sphingosine 1-phosphate (S1P). This is consistent with data that showed that S1P activated both c-Src and p42/p44 mitogen-activated protein kinase (p42/p44 MAPK) in a pertussis toxin (PTX)-sensitive manner in these cells. An essential role for c-Src was confirmed by using the c-Src inhibitor, PP1, which markedly decreased p42/p44 MAPK activation. We have also shown that phosphoinositide 3-kinase (PI-3K) inhibitors (wortmannin and LY294002) decreased p42/p44 MAPK activation. An essential role for PI-3K was supported by experiments that showed that PI-3K activity was increased in Grb-2 immunoprecipitates from S1P-stimulated cells. Significantly, Grb-2 associated PI-3K activity was decreased by pretreatment of cells with PTX. Finally, we have shown that the co-stimulation of cells with platelet-derived growth factor (PDGF) and S1P (which failed to stimulate DNA synthesis) elicited a larger p42/p44 MAPK activation over a 30 min stimulation compared with each agonist alone. This was associated with a S1P-dependent increase in PDGF-stimulated DNA synthesis. These results demonstrate that S1P activates c-Src and Grb-2-PI-3K (intermediates in the p42/p44 MAPK cascade) via a PTX-sensitive mechanism. This action of S1P is consistent with the stimulation of EDG-1 receptors. S1P might also function as a co-mitogen with PDGF, producing a more robust activation of a common permissive signal transduction pathway linked to DNA synthesis. PMID:10051434

  11. Perturbed equilibrium of myosin binding in airway smooth muscle and its implications in bronchospasm.

    PubMed

    Fredberg, J J; Inouye, D S; Mijailovich, S M; Butler, J P

    1999-03-01

    In asthma, the mechanisms relating airway obstruction, hyperresponsiveness, and inflammation remain rather mysterious. We show here that regulation of airway smooth muscle length corresponds to a dynamically equilibrated steady state, not the static mechanical equilibrium that had been previously assumed. This dynamic steady state requires as an essential feature a continuous supply of external mechanical energy (derived from tidal lung inflations) that acts to perturb the interactions of myosin with actin, drive the molecular state of the system far away from thermodynamic equilibrium, and bias the muscle toward lengthening. This mechanism leads naturally to the suggestion that excessive airway narrowing in asthma may be associated with the destabilization of that dynamic process and its resulting collapse back to static equilibrium. With this collapse the muscle undergoes a phase transition and virtually freezes at its static equilibrium length. This mechanism may help to elucidate several unexplained phenomena including the multifactorial origins of airway hyperresponsiveness, how allergen sensitization leads to airway hyperresponsiveness, how hyperresponsiveness can persist long after airway inflammation is resolved, and the inability in asthma of deep inspirations to relax airway smooth muscle. PMID:10051279

  12. The impact of vitamin D on asthmatic human airway smooth muscle.

    PubMed

    Hall, Sannette C; Fischer, Kimberly D; Agrawal, Devendra K

    2016-02-01

    Asthma is a chronic heterogeneous disorder, which involves airway inflammation, airway hyperresponsiveness (AHR) and airway remodeling. The airway smooth muscle (ASM) bundle regulates the broncho-motor tone and plays a critical role in AHR as well as orchestrating inflammation. Vitamin D deficiency has been linked to increased severity and exacerbations of symptoms in asthmatic patients. It has been shown to modulate both immune and structural cells, including ASM cells, in inflammatory diseases. Given that current asthma therapies have not been successful in reversing airway remodeling, vitamin D supplementation as a potential therapeutic option has gained a great deal of attention. Here, we highlight the potential immunomodulatory properties of vitamin D in regulating ASM function and airway inflammation in bronchial asthma. PMID:26634624

  13. A Synthetic Chloride Channel Relaxes Airway Smooth Muscle of the Rat

    PubMed Central

    Yau, Kwok-hei; Mak, Judith Choi-wo; Leung, Susan Wai-sum; Yang, Dan; Vanhoutte, Paul M.

    2012-01-01

    Synthetic ion channels may have potential therapeutic applications, provided they possess appropriate biological activities. The present study was designed to examine the ability of small molecule-based synthetic Cl– channels to modulate airway smooth muscle responsiveness. Changes in isometric tension were measured in rat tracheal rings. Relaxations to the synthetic chloride channel SCC-1 were obtained during sustained contractions to KCl. The anion dependency of the effect of SCC-1 was evaluated by ion substitution experiments. The sensitivity to conventional Cl– transport inhibitors was also tested. SCC-1 caused concentration-dependent relaxations during sustained contractions to potassium chloride. This relaxing effect was dependent on the presence of extracellular Cl– and HCO3−. It was insensitive to conventional Cl– channels/transport inhibitors that blocked the cystic fibrosis transmembrane conductance regulator and calcium-activated Cl– channels. SCC-1 did not inhibit contractions induced by carbachol, endothelin-1, 5-hydroxytryptamine or the calcium ionophore A23187. SCC-1 relaxes airway smooth muscle during contractions evoked by depolarizing solutions. The Cl– conductance conferred by this synthetic compound is distinct from the endogenous transport systems for chloride anions. PMID:23049786

  14. Cigarette smoke-induced mitochondrial fragmentation and dysfunction in human airway smooth muscle

    PubMed Central

    Aravamudan, Bharathi; Kiel, Alexander; Freeman, Michelle; Delmotte, Philippe; Thompson, Michael; Vassallo, Robert; Sieck, Gary C.; Pabelick, Christina M.

    2014-01-01

    The balance between mitochondrial fission and fusion is crucial for mitochondria to perform its normal cellular functions. We hypothesized that cigarette smoke (CS) disrupts this balance and enhances mitochondrial dysfunction in the airway. In nonasthmatic human airway smooth muscle (ASM) cells, CS extract (CSE) induced mitochondrial fragmentation and damages their networked morphology in a concentration-dependent fashion, via increased expression of mitochondrial fission protein dynamin-related protein 1 (Drp1) and decreased fusion protein mitofusin (Mfn) 2. CSE effects on Drp1 vs. Mfn2 and mitochondrial network morphology involved reactive oxygen species (ROS), activation of extracellular signal-regulated kinase (ERK), phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt), protein kinase C (PKC) and proteasome pathways, as well as transcriptional regulation via factors such as NF-κB and nuclear erythroid 2-related factor 2. Inhibiting Drp1 prevented CSE effects on mitochondrial networks and ROS generation, whereas blocking Mfn2 had the opposite, detrimental effect. In ASM from asmatic patients, mitochondria exhibited substantial morphological defects at baseline and showed increased Drp1 but decreased Mfn2 expression, with exacerbating effects of CSE. Overall, these results highlight the importance of mitochondrial networks and their regulation in the context of cellular changes induced by insults such as inflammation (as in asthma) or CS. Altered mitochondrial fission/fusion proteins have a further potential to influence parameters such as ROS and cell proliferation and apoptosis relevant to airway diseases. PMID:24610934

  15. A long-acting β2-adrenergic agonist increases the expression of muscarine cholinergic subtype-3 receptors by activating the β2-adrenoceptor cyclic adenosine monophosphate signaling pathway in airway smooth muscle cells

    PubMed Central

    LIU, YUAN-HUA; WU, SONG-ZE; WANG, GANG; HUANG, NI-WEN; LIU, CHUN-TAO

    2015-01-01

    The persistent administration of β2-adrenergic (β2AR) agonists has been demonstrated to increase the risk of severe asthma, partly due to the induction of tolerance to bronchoprotection via undefined mechanisms. The present study investigated the potential effect of the long-acting β2-adrenergic agonist, formoterol, on the expression of muscarinic M3 receptor (M3R) in rat airway smooth muscle cells (ASMCs). Primary rat ASMCs were isolated and characterized following immunostaining with anti-α-smooth muscle actin antibodies. The protein expression levels of M3R and phospholipase C-β1 (PLCβ1) were characterized by western blot analysis and the production of inositol 1,4,5-trisphosphate (IP3) was determined using an enzyme-linked immunosorbent assay. Formoterol increased the protein expression of M3R in rat ASMCs in a time- and dose-dependent manner, which was significantly inhibited by the β2AR antagonist, ICI118,551 and the cyclic adenosine monophosphate (cAMP) inhibitor, SQ22,536. The increased protein expression of M3R was positively correlated with increased production of PLCβ1 and IP3. Furthermore, treatment with the glucocorticoid, budesonide, and the PLC inhibitor, U73,122, significantly suppressed the formoterol-induced upregulated protein expression levels of M3R and PLCβ1 and production of IP3. The present study demonstrated that formoterol mediated the upregulation of M3R in the rat ASMCs by activating the β2AR-cAMP signaling pathway, resulting in increased expression levels of PLCβ1 and IP3, which are key to inducing bronchoprotection tolerance. Administration of glucocorticoids or a PLC antagonist prevented formoterol-induced bronchoprotection tolerance by suppressing the protein expression of M3R. PMID:25672589

  16. Airway smooth muscle changes in the nitrofen-induced congenital diaphragmatic hernia rat model.

    PubMed

    Belik, Jaques; Davidge, Sandra T; Zhang, Wei; Pan, Jingyi; Greer, John J

    2003-05-01

    In the fetal rat, nitrofen induces congenital diaphragmatic hernia (CDH) and pulmonary vascular remodeling similar to what is observed in the human condition. Airway hyperactivity is common in infants with CDH and attributed to the ventilator-induced airway damage. The purpose of this study was to test the hypothesis that airway smooth muscle mechanical properties are altered in the nitrofen-induced CDH rat model. Lungs from nitrofen-exposed fetuses with hernias (CDH) or intact diaphragm (nitrofen) and untreated fetuses (control) were studied on gestation d 21. The left intrapulmonary artery and bronchi were removed and mounted on a wire myograph, and lung expression, content, and immunolocalization of cyclooxygenases COX-1 and COX-2 were evaluated. Pulmonary artery muscle in the CDH group had significantly (p < 0.01) lower force generation compared with control and nitrofen groups. In contrast, the same generation bronchial smooth muscle of the CDH and nitrofen groups developed higher force compared with control. Whereas no differences were found in endothelium-dependent pulmonary vascular muscle tone, the epithelium-dependent airway muscle relaxation was significantly decreased (p < 0.01) in the CDH and nitrofen groups. The lung mRNA levels of COX-1 and COX-2 were increased in the CDH and nitrofen groups. COX-1 vascular and airway immunostaining, as well as COX-1 and COX-2 lung protein content, were increased in the CDH group. This is the first report of airway smooth muscle abnormalities in the nitrofen-induced fetal rat model of CDH. We speculate that congenital airway muscle changes may be present in the human form of this disease. PMID:12612200

  17. A study of airway smooth muscle in asthmatic and non-asthmatic airways using PS-OCT (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Adams, David C.; Holz, Jasmin A.; Szabari, Margit V.; Hariri, Lida P.; Harris, R. Scott; Cho, Jocelyn L.; Hamilos, Daniel L.; Luster, Andrew D.; Medoff, Benjamin D.; Suter, Melissa J.

    2016-03-01

    Present understanding of the pathophysiological mechanisms of asthma has been severely limited by the lack of an imaging modality capable of assessing airway conditions of asthma patients in vivo. Of particular interest is the role that airway smooth muscle (ASM) plays in the development of asthma and asthma related symptoms. With standard Optical Coherence Tomography (OCT), imaging ASM is often not possible due to poor structural contrast between the muscle and surrounding tissues. A potential solution to this problem is to utilize additional optical contrast factors intrinsic to the tissue, such as birefringence. Due to its highly ordered structure, ASM is strongly birefringent. Previously, we demonstrated that Polarization Sensitive OCT(PS-OCT) has the potential to be used to visualize ASM as well as easily segment it from the surrounding (weakly) birefringent tissue by exploiting a property which allows it to discriminate the orientation of birefringent fibers. We have already validated our technology with a substantial set of histological comparisons made against data obtained ex vivo. In this work we present a comprehensive comparison of ASM distributions in asthmatic and non-asthmatic human volunteers. By isolating the ASM we parameterize its distribution in terms of both thickness and band width, calculated volumetrically over centimeters of airway. Using this data we perform analyses of the asthmatic and non-asthmatic airways using a broad number and variety and subjects.

  18. M2 Muscarinic acetylcholine receptor modulates rat airway smooth muscle cell proliferation

    PubMed Central

    2013-01-01

    Airways chronic inflammatory conditions in asthma and COPD are characterized by tissue remodeling, being smooth muscle hyperplasia, the most important feature. Non-neuronal and neuronal Acetylcholine acting on muscarinic receptors (MAChRs) has been postulated as determinant of tissue remodeling in asthma and COPD by promoting proliferation and phenotypic changes of airway smooth muscle cells (ASMC). The objective was to evaluate proliferative responses to muscarinic agonist as carbamylcholine (Cch) and to identify the MAchR subtype involved. ASMC were isolated from tracheal fragments of Sprague–Dawley rats by enzymatic digestion. Proliferation assays were performed by MTS-PMS method. Viability was confirmed by trypan blue exclusion method. Mitogens as, epidermal growth factor (EGF), Tumor necrosis factor-alpha (TNF-α) and fetal bovine serum (FBS) increased ASMC proliferation (p < 0.05, n = 5). Cch alone increased ASMC proliferation at 24 and 48 hrs. However, combination of Cch with other mitogens exhibited a dual effect, synergistic proliferation effect in the presence of EGF (5 ng/mL) and 5% FBS and inhibiting the proliferation induced by 10% FBS, EGF (10 ng/mL) and TNF-α (10 ng/mL). To determine the MAChR subtype involved in these biological responses, a titration curve of selective muscarinic antagonists were performed. The Cch stimulatory and inhibitory effects on ASCM proliferation was blocked by AF-DX-116 (M2AChR selective antagonist), in greater proportion than 4-DAMP (M3AChR selective antagonist), suggesting that the modulation of muscarinic agonist-induced proliferation is M2AChR mediated responses. Thus, M2AChR can activate multiple signal transduction systems and mediate both effects on ASMC proliferation depending on the plethora and variable airway microenvironments existing in asthma and COPD. PMID:24377382

  19. Chrysin inhibits human airway smooth muscle cells proliferation through the extracellular signal-regulated kinase 1/2 signaling pathway.

    PubMed

    Yao, Jing; Zhang, Yun-Shi; Feng, Gan-Zhu; Du, Qiang

    2015-11-01

    Asthma is a chronic airway inflammatory disease characterized by an increased mass of airway smooth muscle (ASM). Chrysin (5,7-dihydroxyflavone), a natural flavonoid, has been shown to exert multiple biological activities, including anti-inflammatory, anti-proliferative and anti-oxidant effects, as well as the potency to ameliorate asthma in animal models. The objective of the present study was to identify the underlying mechanism of the therapeutic effects of chrysin. The impact of chrysin on basal and platelet-derived growth factor (PDGF)-induced proliferation and apoptosis of human airway smooth muscle cells (HASMCs) was investigated. Furthermore, the activation of the extracellular signal-regulated protein kinase (ERK) signaling pathway was evaluated in HASMCs. The results revealed that chrysin significantly inhibited basal as well as PDGF-induced HASMC proliferation, most likely through the suppression of ERK1/2 phosphorylation. However, chrysin did not significantly reduce PDGF-induced apoptosis of HASMCs. The present study indicated that chrysin may be a promising medication for controlling airway remodeling and clinical manifestations of asthma. PMID:26502995

  20. Relaxant Action of Plumula Nelumbinis Extract on Mouse Airway Smooth Muscle

    PubMed Central

    Tan, Li; Chen, Weiwei; Wei, Ming-Yu; Shen, Jinhua; Yu, Meng-Fei; Yang, Guangzhong; Guo, Donglin; Qin, Gangjian; Ji, Guangju; Liu, Qing-Hua

    2015-01-01

    The traditional herb Plumula Nelumbinis is widely used in the world because it has many biological activities, such as anti-inflammation, antioxidant, antihypertension, and butyrylcholinesterase inhibition. However, the action of Plumula Nelumbinis on airway smooth muscle (ASM) relaxation has not been investigated. A chloroform extract of Plumula Nelumbinis (CEPN) was prepared, which completely inhibited precontraction induced by high K+ in a concentration-dependent manner in mouse tracheal rings, but it had no effect on resting tension. CEPN also blocked voltage-dependent L-type Ca2+ channel- (VDCC-) mediated currents. In addition, ACh-induced precontraction was also completely blocked by CEPN and partially inhibited by nifedipine or pyrazole 3. Besides, CEPN partially reduced ACh-activated nonselective cation channel (NSCC) currents. Taken together, our data demonstrate that CEPN blocked VDCC and NSCC to inhibit Ca2+ influx, resulting in relaxation of precontracted ASM. This finding indicates that CEPN would be a candidate of new potent bronchodilators. PMID:25763092

  1. Computational simulation of human upper airway collapse using a pressure-/state-dependent model of genioglossal muscle contraction under laminar flow conditions

    PubMed Central

    Huang, Yaqi; Malhotra, Atul; White, David P.

    2012-01-01

    A three-element, pressure- and state (sleep and wake) -dependent contraction model of the genioglossal muscle was developed based on the microstructure of skeletal muscle and the cross-bridge theory. This model establishes a direct connection between the contractile forces generated in muscle fibers and the measured electromyogram signals during various upper airway conditions. This effectively avoids the difficulty of determining muscle shortening velocity during complex pharyngeal conditions when modeling the muscle’s contractile behaviors. The activation of the genioglossal muscle under different conditions was then simulated. A sensitivity analysis was performed to determine the effects of varying each modeled parameter on the muscle’s contractile behaviors. This muscle contraction model was then incorporated into our anatomically correct, two-dimensional computational model of the pharyngeal airway to perform a finite-element analysis of air flow, tissue deformation, and airway collapse. The model-predicted muscle deformations are consistent with previous observations regarding upper airway behavior in normal subjects. PMID:15831800

  2. Olfactory Receptors Modulate Physiological Processes in Human Airway Smooth Muscle Cells.

    PubMed

    Kalbe, Benjamin; Knobloch, Jürgen; Schulz, Viola M; Wecker, Christine; Schlimm, Marian; Scholz, Paul; Jansen, Fabian; Stoelben, Erich; Philippou, Stathis; Hecker, Erich; Lübbert, Hermann; Koch, Andrea; Hatt, Hanns; Osterloh, Sabrina

    2016-01-01

    Pathophysiological mechanisms in human airway smooth muscle cells (HASMCs) significantly contribute to the progression of chronic inflammatory airway diseases with limited therapeutic options, such as severe asthma and COPD. These abnormalities include the contractility and hyperproduction of inflammatory proteins. To develop therapeutic strategies, key pathological mechanisms, and putative clinical targets need to be identified. In the present study, we demonstrated that the human olfactory receptors (ORs) OR1D2 and OR2AG1 are expressed at the RNA and protein levels in HASMCs. Using fluorometric calcium imaging, specific agonists for OR2AG1 and OR1D2 were identified to trigger transient Ca(2+) increases in HASMCs via a cAMP-dependent signal transduction cascade. Furthermore, the activation of OR2AG1 via amyl butyrate inhibited the histamine-induced contraction of HASMCs, whereas the stimulation of OR1D2 with bourgeonal led to an increase in cell contractility. In addition, OR1D2 activation induced the secretion of IL-8 and GM-CSF. Both effects were inhibited by the specific OR1D2 antagonist undecanal. We herein provide the first evidence to show that ORs are functionally expressed in HASMCs and regulate pathophysiological processes. Therefore, ORs might be new therapeutic targets for these diseases, and blocking ORs could be an auspicious strategy for the treatment of early-stage chronic inflammatory lung diseases. PMID:27540365

  3. Olfactory Receptors Modulate Physiological Processes in Human Airway Smooth Muscle Cells

    PubMed Central

    Kalbe, Benjamin; Knobloch, Jürgen; Schulz, Viola M.; Wecker, Christine; Schlimm, Marian; Scholz, Paul; Jansen, Fabian; Stoelben, Erich; Philippou, Stathis; Hecker, Erich; Lübbert, Hermann; Koch, Andrea; Hatt, Hanns; Osterloh, Sabrina

    2016-01-01

    Pathophysiological mechanisms in human airway smooth muscle cells (HASMCs) significantly contribute to the progression of chronic inflammatory airway diseases with limited therapeutic options, such as severe asthma and COPD. These abnormalities include the contractility and hyperproduction of inflammatory proteins. To develop therapeutic strategies, key pathological mechanisms, and putative clinical targets need to be identified. In the present study, we demonstrated that the human olfactory receptors (ORs) OR1D2 and OR2AG1 are expressed at the RNA and protein levels in HASMCs. Using fluorometric calcium imaging, specific agonists for OR2AG1 and OR1D2 were identified to trigger transient Ca2+ increases in HASMCs via a cAMP-dependent signal transduction cascade. Furthermore, the activation of OR2AG1 via amyl butyrate inhibited the histamine-induced contraction of HASMCs, whereas the stimulation of OR1D2 with bourgeonal led to an increase in cell contractility. In addition, OR1D2 activation induced the secretion of IL-8 and GM-CSF. Both effects were inhibited by the specific OR1D2 antagonist undecanal. We herein provide the first evidence to show that ORs are functionally expressed in HASMCs and regulate pathophysiological processes. Therefore, ORs might be new therapeutic targets for these diseases, and blocking ORs could be an auspicious strategy for the treatment of early-stage chronic inflammatory lung diseases. PMID:27540365

  4. How the airway smooth muscle in cystic fibrosis reacts in proinflammatory conditions: implications for airway hyper-responsiveness and asthma in cystic fibrosis.

    PubMed

    McCuaig, Sarah; Martin, James G

    2013-04-01

    Among patients with cystic fibrosis there is a high prevalence (40-70%) of asthma signs and symptoms such as cough and wheezing and airway hyper-responsiveness to inhaled histamine or methacholine. Whether these abnormal airway responses are due to a primary deficiency in the cystic fibrosis transmembrane conductance regulator (CFTR) or are secondary to the inflammatory environment in the cystic fibrosis lungs is not clear. A role for the CFTR in smooth muscle function is emerging, and alterations in contractile signalling have been reported in CFTR-deficient airway smooth muscle. Persistent bacterial infection, especially with Pseudomonas aeruginosa, stimulates interleukin-8 release from the airway epithelium, resulting in neutrophilic inflammation. Increased neutrophilia and skewing of CFTR-deficient T-helper cells to type 2 helper T cells creates an inflammatory environment characterised by high concentrations of tumour necrosis factor α, interleukin-8, and interleukin-13, which might all contribute to increased contractility of airway smooth muscle in cystic fibrosis. An emerging role of interleukin-17, which is raised in patients with cystic fibrosis, in airway smooth muscle proliferation and hyper-responsiveness is apparent. Increased understanding of the molecular mechanisms responsible for the altered smooth muscle physiology in patients with cystic fibrosis might provide insight into airway dysfunction in this disease. PMID:24429094

  5. Three Paradigms of Airway Smooth Muscle Hyperresponsiveness in Young Guinea Pigs

    PubMed Central

    Chitano, Pasquale; Wang, Lu; Murphy, Thomas M.

    2008-01-01

    Evidence for contributions of airway smooth muscle (ASM) to the hyperresponsiveness of newborn and juvenile airways continues to accumulate. In our laboratory three novel paradigms of hyperresponsiveness of newborn and young ASM have recently emerged using a guinea pig model of maturation in three age groups-- 1 week (newborn); 3 week (juvenile) and 2−3 months (adult). These include 1) evidence for a natural decline after newborn and juvenile life of the shortening velocity of ASM shortening associated with a decrease in regulatory myosin light chain (MLC) phosphorylation and a parallel decline in the content of MLC kinase. Associated with the decrease in ASM shortening with age is an increase in the internal resistance to shortening. This relationship can be approximated as dP/dtmax ≈ dP/dLpassive × dL/dtmax (the maximal rate of increase of active stress generation ≈ the passive stiffness × the maximal shortening velocity V0). 2) The second paradigm demonstrates that newborn ASM, unlike that in adults, does not relax with prolonged electrical field stimulation. The impaired relaxation is related to changes in prostaglandin synthesis and acetylcholinesterase function; 3) the third paradigm demonstrates that while oscillatory strain serves to relax adult ASM, the response in newborns is the potentiation of active stress. This is related to developmental changes in the cytoskeleton. Oscillatory stiffness is shown to relate inversely to the expression of myosin light chain kinase. This suggests that developmental changes in shortening relate inversely to the stiffness of the ASM early in shortening, suggesting a dynamic role for the cytoskeleton in facilitating and opposing ASM shortening. Together these paradigms demonstrate that ASM contributes by multiple mechanisms to the natural hyperresponsiveness of newborn and juvenile airways. Future studies will elaborate the mechanisms and extend these paradigms relate to ASM hyperresponsiveness that is increased

  6. Airway smooth muscle NOX4 is upregulated and modulates ROS generation in COPD.

    PubMed

    Hollins, Fay; Sutcliffe, Amanda; Gomez, Edith; Berair, Rachid; Russell, Richard; Szyndralewiez, Cédric; Saunders, Ruth; Brightling, Christopher

    2016-01-01

    The burden of oxidative stress is increased in chronic obstructive pulmonary disease (COPD). However, whether the intra-cellular mechanisms controlling the oxidant/anti-oxidant balance in structural airway cells such as airway smooth muscle in COPD is altered is unclear. We sought to determine whether the expression of the NADPH oxidase (NOX)-4 is increased in airway smooth muscle in COPD both in vivo and primary cells in vitro and its role in hydrogen peroxide-induced reactive oxygen species generation. We found that in vivo NOX4 expression was up-regulated in the airway smooth muscle bundle in COPD (n = 9) and healthy controls with >20 pack year history (n = 4) compared to control subjects without a significant smoking history (n = 6). In vitro NOX4 expression was increased in airway smooth muscle cells from subjects with COPD (n = 5) compared to asthma (n = 7) and upregulated following TNF-α stimulation. Hydrogen peroxide-induced reactive oxygen species generation by airway smooth muscle cells in COPD (n = 5) was comparable to healthy controls (n = 9) but lower than asthma (n = 5); and was markedly attenuated by NOX4 inhibition. Our findings demonstrate that NOX4 expression is increased in vivo and in vitro in COPD and although we did not observe an intrinsic increase in oxidant-induced reactive oxygen species generation in COPD, it was reduced markedly by NOX4 inhibition supporting a potential therapeutic role for NOX4 in COPD. PMID:27435477

  7. A novel bronchial ring bioassay for the evaluation of small airway smooth muscle function in mice.

    PubMed

    Liu, John Q; Yang, Dennis; Folz, Rodney J

    2006-08-01

    Advances in our understanding of murine airway physiology have been hindered by the lack of suitable, ex vivo, small airway bioassay systems. In this study, we introduce a novel small murine airway bioassay system that permits the physiological and pharmacological study of intrapulmonary bronchial smooth muscle via a bronchial ring (BR) preparation utilizing BR segments as small as 200 microm in diameter. Using this ex vivo BR bioassay, we characterized small airway smooth muscle contraction and relaxation in the presence and absence of bronchial epithelium. In control BRs, the application of mechanical stretch is followed by spontaneous bronchial smooth muscle relaxation. BRs pretreated with methacholine (MCh) partially attenuate this stretch-induced relaxation by as much as 42% compared with control. MCh elicited a dose-dependent bronchial constriction with a maximal tension (E(max)) of 8.7 +/- 0.2 mN at an EC(50) of 0.33 +/- 0.02 microM. In the presence of nifedipine, ryanodine, 2-aminoethoxydiphenyl borate, and SKF-96365, E(max) to MCh was significantly reduced. In epithelium-denuded BRs, MCh-induced contraction was significantly enhanced to 11.4 +/- 1.0 mN with an EC(50) of 0.16 +/- 0.04 microM (P < 0.01). Substance P relaxed MCh-precontracted BR by 62.1%; however, this bronchial relaxation effect was completely lost in epithelium-denuded BRs. Papaverine virtually abolished MCh-induced constriction in both epithelium-intact and epithelium-denuded bronchial smooth muscle. In conclusion, this study introduces a novel murine small airway BR bioassay that allows for the physiological study of smooth muscle airway contractile responses that may aid in our understanding of the pathophysiology of asthma. PMID:16648239

  8. IL-9-mediated induction of eotaxin1/CCL11 in human airway smooth muscle cells.

    PubMed

    Gounni, Abdelilah Soussi; Hamid, Qutayba; Rahman, Sahidur M; Hoeck, Jutta; Yang, Jie; Shan, Lianyu

    2004-08-15

    Recent work has shown the potential importance of IL-9 in allergic diseases. The development of transgenic mice overexpressing IL-9 has suggested a key role for this cytokine in the development of the asthmatic phenotype including airway eosinophilia. In this study, we evaluated the expression of the IL-9R and the effects of IL-9 on human ASM cells by examining the release of Th2-associated chemokines (eotaxin1/CCL11 and thymus- and activation-regulated chemokine (TARC)/CCL17). IL-9R alpha-chain mRNA and surface expression were detected in cultured human airway smooth muscle (ASM) cells. In addition, primary cultured ASM cells, as well as bronchial smooth muscle cells within biopsies of asthmatics and not control subjects, revealed IL-9R protein expression. IL-9 stimulation of human ASM cells resulted in release of eotaxin1/CCL11, but had no effect on the release of TARC/CCL17, in time- and dose-dependent manner. Moreover, in vitro chemotaxis assay demonstrated that conditioned medium from IL-9-stimulated ASM cells attracted human eosinophils. Neutralizing Abs to IL-9, but not to IL-4 or IL-13, reduced significantly IL-9-induced production of eotaxin1/CCL11 from ASM cells. Interestingly, real-time RT-PCR showed that IL-9 up-regulated eotaxin1/CCL11 mRNA expression, but had no effect on TARC/CCL17. Treatment with Act D abrogates IL-9-induced eotaxin1/CCL11 mRNA and protein release by ASM cells. Finally, transfection study using eotaxin1/CCL11 promoter luciferase construct confirmed that IL-9 induced eotaxin1/CCL11 at the transcriptional level. Taken together, these data provide new evidence demonstrating that IL-9-dependent activation of ASM cells contributes to eosinophilic inflammation observed in asthma. PMID:15294996

  9. The Pro-Proliferative Effects of Nicotine and Its Underlying Mechanism on Rat Airway Smooth Muscle Cells

    PubMed Central

    He, Fang; Li, Bing; Zhao, Zhuxiang; Zhou, Yumin; Hu, Guoping; Zou, Weifeng; Hong, Wei; Zou, Yimin; Jiang, Changbin; Zhao, Dongxing; Ran, Pixin

    2014-01-01

    Recent studies have shown that nicotine, a major component of cigarette smoke, can stimulate the proliferation of non-neuronal cells. Cigarette smoking can promote a variety of pulmonary and cardiovascular diseases, such as chronic obstructive pulmonary disease (COPD), atherosclerosis, and cancer. A predominant feature of COPD is airway remodeling, which includes increased airway smooth muscle (ASM) mass. The mechanisms underlying ASM remodeling in COPD have not yet been fully elucidated. Here, we show that nicotine induces a profound and time-dependent increase in DNA synthesis in rat airway smooth muscle cells (RASMCs) in vitro. Nicotine also significantly increased the number of RASMCs, which was associated with the increased expression of Cyclin D1, phosphorylation of the retinoblastoma protein (RB) and was dependent on the activation of Akt. The activation of Akt by nicotine occurred within minutes and depended upon the nicotinic acetylcholine receptors (nAchRs). Activated Akt increased the phosphorylation of downstream substrates such as GSK3β. Our data suggest that the binding of nicotine to the nAchRs on RASMCs can regulate cellular proliferation by activating the Akt pathway. PMID:24690900

  10. Hyaluronic acid influence on platelet-induced airway smooth muscle cell proliferation

    SciTech Connect

    Svensson Holm, Ann-Charlotte B.; Bengtsson, Torbjoern; Grenegard, Magnus; Lindstroem, Eva G.

    2012-03-10

    Hyaluronic acid (HA) is one of the main components of the extracellular matrix (ECM) and is expressed throughout the body including the lung and mostly in areas surrounding proliferating and migrating cells. Furthermore, platelets have been implicated as important players in the airway remodelling process, e.g. due to their ability to induce airway smooth muscle cell (ASMC) proliferation. The aim of the present study was to investigate the role of HA, the HA-binding surface receptor CD44 and focal adhesion kinase (FAK) in platelet-induced ASMC proliferation. Proliferation of ASMC was measured using the MTS-assay, and we found that the CD44 blocking antibody and the HA synthase inhibitor 4-Methylumbelliferone (4-MU) significantly inhibited platelet-induced ASMC proliferation. The interaction between ASMC and platelets was studied by fluorescent staining of F-actin. In addition, the ability of ASMC to synthesise HA was investigated by fluorescent staining using biotinylated HA-binding protein and a streptavidin conjugate. We observed that ASMC produced HA and that a CD44 blocking antibody and 4-MU significantly inhibited platelet binding to the area surrounding the ASMC. Furthermore, the FAK-inhibitor PF 573228 inhibited platelet-induced ASMC proliferation. Co-culture of ASMC and platelets also resulted in increased phosphorylation of FAK as detected by Western blot analysis. In addition, 4-MU significantly inhibited the increased FAK-phosphorylation. In conclusion, our findings demonstrate that ECM has the ability to influence platelet-induced ASMC proliferation. Specifically, we propose that HA produced by ASMC is recognised by platelet CD44. The platelet/HA interaction is followed by FAK activation and increased proliferation of co-cultured ASMC. We also suggest that the mitogenic effect of platelets represents a potential important and novel mechanism that may contribute to airway remodelling.

  11. Prostaglandin E2 induces expression of MAPK phosphatase 1 (MKP-1) in airway smooth muscle cells.

    PubMed

    Rumzhum, Nowshin N; Ammit, Alaina J

    2016-07-01

    Prostaglandin E2 (PGE2) is a prostanoid with diverse actions in health and disease. In chronic respiratory diseases driven by inflammation, PGE2 has both positive and negative effects. An enhanced understanding of the receptor-mediated cellular signalling pathways induced by PGE2 may help us separate the beneficial properties from unwanted actions of this important prostaglandin. PGE2 is known to exert anti-inflammatory and bronchoprotective actions in human airways. To date however, whether PGE2 increases production of the anti-inflammatory protein MAPK phosphatase 1 (MKP-1) was unknown. We address this herein and use primary cultures of human airway smooth muscle (ASM) cells to show that PGE2 increases MKP-1 mRNA and protein upregulation in a concentration-dependent manner. We explore the signalling pathways responsible and show that PGE2-induces CREB phosphorylation, not p38 MAPK activation, in ASM cells. Moreover, we utilize selective antagonists of EP2 (PF-04418948) and EP4 receptors (GW 627368X) to begin to identify EP-mediated functional outcomes in ASM cells in vitro. Taken together with earlier studies, our data suggest that PGE2 increases production of the anti-inflammatory protein MKP-1 via cAMP/CREB-mediated cellular signalling in ASM cells and demonstrates that EP2 may, in part, be involved. PMID:27108790

  12. Interdicting Gq Activation in Airway Disease by Receptor-Dependent and Receptor-Independent Mechanisms.

    PubMed

    Carr, Richard; Koziol-White, Cynthia; Zhang, Jie; Lam, Hong; An, Steven S; Tall, Gregory G; Panettieri, Reynold A; Benovic, Jeffrey L

    2016-01-01

    Gαqβγ heterotrimer (Gq), an important mediator in the pathology of airway disease, plays a central role in bronchoconstriction and airway remodeling, including airway smooth muscle growth and inflammation. Current therapeutic strategies to treat airway disease include the use of muscarinic and leukotriene receptor antagonists; however, these pharmaceuticals demonstrate a limited clinical efficacy as multiple Gq-coupled receptor subtypes contribute to these pathologies. Thus, broadly inhibiting the activation of Gq may be an advantageous therapeutic approach. Here, we investigated the effects of broadly inhibiting Gq activation in vitro and ex vivo using receptor-dependent and receptor-independent strategies. P4pal-10 is a protease activated receptor 4-derived pepducin that exhibits efficacy toward multiple Gq-coupled receptors. Mechanistic studies demonstrated that P4pal-10 selectively inhibits all G protein coupling to several Gq-coupled receptors, including protease activated receptor 1, muscarinic acetylcholine M3, and histamine H1 receptors, while demonstrating no direct effect on Gq. We also evaluated the ability of FR900359, also known as UBO-QIC, to directly inhibit Gq activation. FR900359 inhibited spontaneous Gαq nucleotide exchange, while having little effect on Gαsβγ, Gαiβγ, or Gα12/13βγ heterotrimer activity. Both P4pal-10 and FR900359 inhibited Gq-mediated intracellular signaling and primary human airway smooth muscle growth, whereas only FR900359 effectively interdicted agonist-promoted airway contraction in human precision cut lung slices. These studies serve as a proof of concept that the broad-based inhibition of Gq activation may be a useful therapeutic approach to treat multiple common pathologies of airway disease. PMID:26464325

  13. Cyclic mechanical strain-induced proliferation and migration of human airway smooth muscle cells: role of EMMPRIN and MMPs.

    PubMed

    Hasaneen, Nadia A; Zucker, Stanley; Cao, Jian; Chiarelli, Christian; Panettieri, Reynold A; Foda, Hussein D

    2005-09-01

    Airway smooth muscle (ASM) proliferation and migration are major components of airway remodeling in asthma. Asthmatic airways are exposed to mechanical strain, which contributes to their remodeling. Matrix metalloproteinase (MMP) plays an important role in remodeling. In the present study, we examined if the mechanical strain of human ASM (HASM) cells contributes to their proliferation and migration and the role of MMPs in this process. HASM were exposed to mechanical strain using the FlexCell system. HASM cell proliferation, migration and MMP release, activation, and expression were assessed. Our results show that cyclic strain increased the proliferation and migration of HASM; cyclic strain increased release and activation of MMP-1, -2, and -3 and membrane type 1-MMP; MMP release was preceded by an increase in extracellular MMP inducer; Prinomastat [a MMP inhibitor (MMPI)] significantly decreased cyclic strain-induced proliferation and migration of HASM; and the strain-induced increase in the release of MMPs was accompanied by an increase in tenascin-C release. In conclusion, cyclic mechanical strain plays an important role in HASM cell proliferation and migration. This increase in proliferation and migration is through an increase in MMP release and activation. Pharmacological MMPIs should be considered in the pursuit of therapeutic options for airway remodeling in asthma. PMID:16014803

  14. Diacylglycerol-containing docosahexaenoic acid in acyl chain modulates airway smooth muscle tone.

    PubMed

    Hichami, Aziz; Morin, Caroline; Rousseau, Eric; Khan, Naim A

    2005-10-01

    We synthesized and assessed the role of a diacylglycerol (DAG)-containing docosahexaenoic acid (DHA), that is, 1-stearoyl-2-docosahexaenoyl-sn-glycerol (SDHG), in the contraction of guinea pig airway smooth muscle (ASM). We compared its action with 1-stearoyl-2-arachidonoyl-sn-glycerol (SAG) and 1,2-dioctanoyl-sn-glycerol (1,2-DiC8), a stable DAG analog. The three DAGs (SAG, SDHG, and 1,2-DiC8) induced reversible concentration-dependent contraction of ASM. SDHG induced higher guinea pig ASM contraction than did SAG and 1,2-DiC8. The effects of SDHG were blocked, to different extents, by nifedipine (L-type Ca2+ channel blocker). By employing GF-109203X (protein kinase C [PKC] inhibitor) and lanthanum (La3+), a nonselective cation channel blocker, we observed that SDHG evoked ASM contractile response via PKC-dependent and PKC-independent (but Ca2+-dependent) pathways. Interestingly, SAG exerted its action only by increasing [Ca2+]i and did not require PKC activation. To probe the implication of calcium mobilization, we employed thapsigargin (TG), which also induced ASM contraction in a calcium-dependent manner. SDHG and 1,2-DiC8, in a PKC-dependent manner, induced the phosphorylation of CPI-17 (myosin light chain phosphatase inhibitor of 17 kD). Furthermore, SAG and TG failed to phosphorylate CPI-17 in ASM cells. Our results suggest that different DAG species, produced during a dietary supplementation with fatty acids, could modulate the reactivity of airway smooth muscles in a PKC-dependent and -independent manner, and hence, may play a critical role in health and disease. PMID:15961724

  15. Activity of abundant antimicrobials of the human airway.

    PubMed

    Travis, S M; Conway, B A; Zabner, J; Smith, J J; Anderson, N N; Singh, P K; Greenberg, E P; Welsh, M J

    1999-05-01

    Human airways produce several antimicrobial factors; the most abundant are lysozyme and lactoferrin. Despite their likely importance in preventing infection, and their possible key role in the pathogenesis of cystic fibrosis (CF), we know little about their antibacterial activity in the context of the CF airway. We found that abundant airway antimicrobial factors kill common CF pathogens, although Burkholderia was relatively resistant. To study the antibacterial activity, we developed a rapid, sensitive, and quantitative in vitro luminescence assay. Because NaCl concentrations may be elevated in CF airway surface liquid, we tested the effect of salt on antibacterial activity. Activity of individual factors and of airway lavage fluid was inhibited by high ionic strength, and it was particularly sensitive to divalent cations. However, it was not inhibited by nonionic osmolytes and thus did not require hypotonic liquid. The inhibition by ionic strength could be partially compensated by increased concentrations of antibacterial factors, thus there was no one unique salt concentration for inhibition. CF airway secretions also contain abundant mucin and elastase; however, these had no effect on antibacterial activity of lysozyme, lactoferrin, or airway lavage fluids. When studied at low NaCl concentrations, CF and non-CF airway lavage fluids contained similar levels of antibacterial activity. These results suggest approaches toward developing treatments aimed at preventing or reducing airway infections in individuals with CF. PMID:10226057

  16. O3-induced mucosa-linked airway muscle hyperresponsiveness in the guinea pig

    SciTech Connect

    Murlas, C.G.; Murphy, T.P.; Chodimella, V. )

    1990-07-01

    We investigated the effects of ozone exposure (3.0 ppm, 2 h) on the responsiveness of guinea pig airway muscle in vitro from animals developing bronchial hyperreactivity. Muscarinic reactivity in vivo was determined by measuring specific airway resistance (sRaw) in response to increasing concentrations of aerosolized acetylcholine (ACh) administered before and 30 min after exposure. Immediately after reactivity testing, multiple tracheal rings from ozone- and air-exposed animals were prepared and the contractile responses to increasing concentrations of substance P, ACh, or KCl were assessed in the presence of 10 microM indomethacin with or without 1 microM phosphoramidon, an inhibitor of neutral endopeptidase. Isometric force generation in vitro was measured on stimulation by cumulative concentrations of the agonists, and force generation (in g/cm2) was calculated after determination of muscle cross-sectional area. The smooth muscle of mucosa-intact airways from guinea pigs with ozone-induced bronchial hyper-reactivity proved to be hyperresponsive in vitro to substance P and ACh but not to KCl. Pretreatment with phosphoramidon abolished the increase in substance P responsiveness but had no effect on muscarinic hyperresponsiveness after ozone exposure. Furthermore, substance P responsiveness was not augmented in ozone-exposed airways in which the mucosa had been removed before testing in vitro. Likewise, muscarinic hyperresponsiveness was not present in ozone-exposed airways without mucosa. Our data indicate that airway smooth muscle responsiveness is increased in guinea pigs with ozone-induced bronchial hyperreactivity and suggest that this hyperresponsiveness may be linked to non-cyclooxygenase mucosa-derived factors.

  17. A novel role for RhoA GTPase in the regulation of airway smooth muscle contraction.

    PubMed

    Zhang, Wenwu; Huang, Youliang; Wu, Yidi; Gunst, Susan J

    2015-02-01

    Recent studies have demonstrated a novel molecular mechanism for the regulation of airway smooth muscle (ASM) contraction by RhoA GTPase. In ASM tissues, both myosin light chain (MLC) phosphorylation and actin polymerization are required for active tension generation. RhoA inactivation dramatically suppresses agonist-induced tension development and completely inhibits agonist-induced actin polymerization, but only slightly reduces MLC phosphorylation. The inhibition of MLC phosphatase does not reverse the effects of RhoA inactivation on contraction or actin polymerization. Thus, RhoA regulates ASM contraction through its effects on actin polymerization rather than MLC phosphorylation. Contractile stimulation of ASM induces the recruitment and assembly of paxillin, vinculin, and focal adhesion kinase (FAK) into membrane adhesion complexes (adhesomes) that regulate actin polymerization by catalyzing the activation of cdc42 GTPase by the G-protein-coupled receptor kinase-interacting target (GIT) - p21-activated kinase (PAK) - PAK-interacting exchange factor (PIX) complex. Cdc42 is a necessary and specific activator of the actin filament nucleation activator, N-WASp. The recruitment and activation of paxillin, vinculin, and FAK is prevented by RhoA inactivation, thus preventing cdc42 and N-WASp activation. We conclude that RhoA regulates ASM contraction by catalyzing the assembly and activation of membrane adhesome signaling modules that regulate actin polymerization, and that the RhoA-mediated assembly of adhesome complexes is a fundamental step in the signal transduction process in response to a contractile agonist. PMID:25531582

  18. Does smooth muscle in an intact airway undergo length adaptation during a sustained change in transmural pressure?

    PubMed

    Ansell, Thomas K; McFawn, Peter K; McLaughlin, Robert A; Sampson, David D; Eastwood, Peter R; Hillman, David R; Mitchell, Howard W; Noble, Peter B

    2015-03-01

    In isolated airway smooth muscle (ASM) strips, an increase or decrease in ASM length away from its current optimum length causes an immediate reduction in force production followed by a gradual time-dependent recovery in force, a phenomenon termed length adaptation. In situ, length adaptation may be initiated by a change in transmural pressure (Ptm), which is a primary physiological determinant of ASM length. The present study sought to determine the effect of sustained changes in Ptm and therefore, ASM perimeter, on airway function. We measured contractile responses in whole porcine bronchial segments in vitro before and after a sustained inflation from a baseline Ptm of 5 cmH2O to 25 cmH2O, or deflation to -5 cmH2O, for ∼50 min in each case. In one group of airways, lumen narrowing and stiffening in response to electrical field stimulation (EFS) were assessed from volume and pressure signals using a servo-controlled syringe pump with pressure feedback. In a second group of airways, lumen narrowing and the perimeter of the ASM in situ were determined by anatomical optical coherence tomography. In a third group of airways, active tension was determined under isovolumic conditions. Both inflation and deflation reduced the contractile response to EFS. Sustained Ptm change resulted in a further decrease in contractile response, which returned to baseline levels upon return to the baseline Ptm. These findings reaffirm the importance of Ptm in regulating airway narrowing. However, they do not support a role for ASM length adaptation in situ under physiological levels of ASM lengthening and shortening. PMID:25729015

  19. Active vs. inactive muscle (image)

    MedlinePlus

    ... may lose 20 to 40 percent of their muscle -- and, along with it, their strength -- as they ... have found that a major reason people lose muscle is because they stop doing everyday activities that ...

  20. The Oligo Fucoidan Inhibits Platelet-Derived Growth Factor-Stimulated Proliferation of Airway Smooth Muscle Cells

    PubMed Central

    Yang, Chao-Huei; Tsao, Chiung-Fang; Ko, Wang-Sheng; Chiou, Ya-Ling

    2016-01-01

    In the pathogenesis of asthma, the proliferation of airway smooth muscle cells (ASMCs) is a key factor in airway remodeling and causes airway narrowing. In addition, ASMCs are also the effector cells of airway inflammation. Fucoidan extracted from marine brown algae polysaccharides has antiviral, antioxidant, antimicrobial, anticlotting, and anticancer properties; however, its effectiveness for asthma has not been elucidated thus far. Platelet-derived growth factor (PDGF)-treated primary ASMCs were cultured with or without oligo-fucoidan (100, 500, or 1000 µg/mL) to evaluate its effects on cell proliferation, cell cycle, apoptosis, and Akt, ERK1/2 signaling pathway. We found that PDGF (40 ng/mL) increased the proliferation of ASMCs by 2.5-fold after 48 h (p < 0.05). Oligo-fucoidan reduced the proliferation of PDGF-stimulated ASMCs by 75%–99% after 48 h (p < 0.05) and induced G1/G0 cell cycle arrest, but did not induce apoptosis. Further, oligo-fucoidan supplementation reduced PDGF-stimulated extracellular signal-regulated kinase (ERK1/2), Akt, and nuclear factor (NF)-κB phosphorylation. Taken together, oligo-fucoidan supplementation might reduce proliferation of PDGF-treated ASMCs through the suppression of ERK1/2 and Akt phosphorylation and NF-κB activation. The results provide basis for future animal experiments and human trials. PMID:26761017

  1. Evidence of hypoxic tolerance in weak upper airway muscle from young mdx mice.

    PubMed

    Burns, David P; O'Halloran, Ken D

    2016-06-01

    Duchenne muscular dystrophy (DMD) is a genetic disease characterised by deficiency in the protein dystrophin. The respiratory system is weakened and patients suffer from sleep disordered breathing and hypoventilation culminating in periods of hypoxaemia. We examined the effects of an acute (6h) hypoxic stress on sternohyoid muscle function (representative pharyngeal dilator). 8 week old male, wild-type (WT; C57BL/10ScSnJ; n=18) and mdx (C57BL/10ScSn-Dmd(mdx)/J; n=16) mice were exposed to sustained hypoxia (FIO2=0.10) or normoxia. Muscle functional properties were examined ex vivo. Additional WT (n=5) and mdx (n=5) sternohyoid muscle was exposed to an anoxic challenge. Sternohyoid dysfunction was observed in mdx mice with significant reductions in force and power. Following exposure to the acute in vivo hypoxic stress, WT sternohyoid muscle showed evidence of functional impairment (reduced force, work and power). Conversely, mdx sternohyoid showed an apparent tolerance to the acute hypoxic stress. This tolerance was not maintained for mdx following a severe hypoxic stress. A dysfunctional upper airway muscle phenotype is present at 8 weeks of age in the mdx mouse, which may have implications for the control of airway patency in DMD. Hypoxic tolerance in mdx respiratory muscle is suggestive of adaptation to chronic hypoxia, which could be present due to respiratory morbidity. We speculate a role for hypoxia in mdx respiratory muscle morbidity. PMID:26691169

  2. Iptakalim inhibits PDGF-BB-induced human airway smooth muscle cells proliferation and migration

    SciTech Connect

    Liu, Wenrui; Kong, Hui; Zeng, Xiaoning; Wang, Jingjing; Wang, Zailiang; Yan, Xiaopei; Wang, Yanli; Xie, Weiping Wang, Hong

    2015-08-15

    Chronic airway diseases are characterized by airway remodeling which is attributed partly to the proliferation and migration of airway smooth muscle cells (ASMCs). ATP-sensitive potassium (K{sub ATP}) channels have been identified in ASMCs. Mount evidence has suggested that K{sub ATP} channel openers can reduce airway hyperresponsiveness and alleviate airway remodeling. Opening K{sup +} channels triggers K{sup +} efflux, which leading to membrane hyperpolarization, preventing Ca{sup 2+}entry through closing voltage-operated Ca{sup 2+} channels. Intracellular Ca{sup 2+} is the most important regulator of muscle contraction, cell proliferation and migration. K{sup +} efflux decreases Ca{sup 2+} influx, which consequently influences ASMCs proliferation and migration. As a K{sub ATP} channel opener, iptakalim (Ipt) has been reported to restrain the proliferation of pulmonary arterial smooth muscle cells (PASMCs) involved in vascular remodeling, while little is known about its impact on ASMCs. The present study was designed to investigate the effects of Ipt on human ASMCs and the mechanisms underlying. Results obtained from cell counting kit-8 (CCK-8), flow cytometry and 5-ethynyl-2′-deoxyuridine (EdU) incorporation showed that Ipt significantly inhibited platelet-derived growth factor (PDGF)-BB-induced ASMCs proliferation. ASMCs migration induced by PDGF-BB was also suppressed by Ipt in transwell migration and scratch assay. Besides, the phosphorylation of Ca{sup 2+}/calmodulin-dependent kinase II (CaMKII), extracellular regulated protein kinases 1/2 (ERK1/2), protein kinase B (Akt), and cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) were as well alleviated by Ipt administration. Furthermore, we found that the inhibition of Ipt on the PDGF-BB-induced proliferation and migration in human ASMCs was blocked by glibenclamide (Gli), a selective K{sub ATP} channel antagonist. These findings provide a strong evidence to support that Ipt

  3. Kv7 potassium channels in airway smooth muscle cells: signal transduction intermediates and pharmacological targets for bronchodilator therapy.

    PubMed

    Brueggemann, Lioubov I; Kakad, Priyanka P; Love, Robert B; Solway, Julian; Dowell, Maria L; Cribbs, Leanne L; Byron, Kenneth L

    2012-01-01

    Expression and function of Kv7 (KCNQ) voltage-activated potassium channels in guinea pig and human airway smooth muscle cells (ASMCs) were investigated by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), patch-clamp electrophysiology, and precision-cut lung slices. qRT-PCR revealed expression of multiple KCNQ genes in both guinea pig and human ASMCs. Currents with electrophysiological and pharmacological characteristics of Kv7 currents were measured in freshly isolated guinea pig and human ASMCs. In guinea pig ASMCs, Kv7 currents were significantly suppressed by application of the bronchoconstrictor agonists methacholine (100 nM) or histamine (30 μM), but current amplitudes were restored by addition of a Kv7 channel activator, flupirtine (10 μM). Kv7 currents in guinea pig ASMCs were also significantly enhanced by another Kv7.2-7.5 channel activator, retigabine, and by celecoxib and 2,5-dimethyl celecoxib. In precision-cut human lung slices, constriction of airways by histamine was significantly reduced in the presence of flupirtine. Kv7 currents in both guinea pig and human ASMCs were inhibited by the Kv7 channel blocker XE991. In human lung slices, XE991 induced robust airway constriction, which was completely reversed by addition of the calcium channel blocker verapamil. These findings suggest that Kv7 channels in ASMCs play an essential role in the regulation of airway diameter and may be targeted pharmacologically to relieve airway hyperconstriction induced by elevated concentrations of bronchoconstrictor agonists. PMID:21964407

  4. Kv7 potassium channels in airway smooth muscle cells: signal transduction intermediates and pharmacological targets for bronchodilator therapy

    PubMed Central

    Brueggemann, Lioubov I.; Kakad, Priyanka P.; Love, Robert B.; Solway, Julian; Dowell, Maria L.; Cribbs, Leanne L.

    2012-01-01

    Expression and function of Kv7 (KCNQ) voltage-activated potassium channels in guinea pig and human airway smooth muscle cells (ASMCs) were investigated by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), patch-clamp electrophysiology, and precision-cut lung slices. qRT-PCR revealed expression of multiple KCNQ genes in both guinea pig and human ASMCs. Currents with electrophysiological and pharmacological characteristics of Kv7 currents were measured in freshly isolated guinea pig and human ASMCs. In guinea pig ASMCs, Kv7 currents were significantly suppressed by application of the bronchoconstrictor agonists methacholine (100 nM) or histamine (30 μM), but current amplitudes were restored by addition of a Kv7 channel activator, flupirtine (10 μM). Kv7 currents in guinea pig ASMCs were also significantly enhanced by another Kv7.2–7.5 channel activator, retigabine, and by celecoxib and 2,5-dimethyl celecoxib. In precision-cut human lung slices, constriction of airways by histamine was significantly reduced in the presence of flupirtine. Kv7 currents in both guinea pig and human ASMCs were inhibited by the Kv7 channel blocker XE991. In human lung slices, XE991 induced robust airway constriction, which was completely reversed by addition of the calcium channel blocker verapamil. These findings suggest that Kv7 channels in ASMCs play an essential role in the regulation of airway diameter and may be targeted pharmacologically to relieve airway hyperconstriction induced by elevated concentrations of bronchoconstrictor agonists. PMID:21964407

  5. Human Lung Mast Cell Products Regulate Airway Smooth Muscle CXCL10 Levels

    PubMed Central

    Alkhouri, H.; Cha, V.; Tong, K.; Moir, L. M.; Armour, C. L.; Hughes, J. M.

    2014-01-01

    In asthma, the airway smooth muscle (ASM) produces CXCL10 which may attract CXCR3+ mast/T cells to it. Our aim was to investigate the effects of mast cell products on ASM cell CXCL10 production. ASM cells from people with and without asthma were stimulated with IL-1β, TNF-α, and/or IFNγ and treated with histamine (1–100 μM) ± chlorpheniramine (H1R antagonist; 1 μM) or ranitidine (H2R antagonist; 50 μM) or tryptase (1 nM) ± leupeptin (serine protease inhibitor; 50 μM), heat-inactivated tryptase, or vehicle for 4 h or 24 h. Human lung mast cells (MC) were isolated and activated with IgE/anti-IgE and supernatants were collected after 2 h or 24 h. The supernatants were added to ASM cells for 48 h and ASM cell CXCL10 production detected using ELISA (protein) and real-time PCR (mRNA). Histamine reduced IL-1β/TNF-α-induced CXCL10 protein, but not mRNA, levels independent of H1 and H2 receptor activation, whereas tryptase and MC 2 h supernatants reduced all cytokine-induced CXCL10. Tryptase also reduced CXCL10 levels in a cell-free system. Leupeptin inhibited the effects of tryptase and MC 2 h supernatants. MC 24 h supernatants contained TNF-α and amplified IFNγ-induced ASM cell CXCL10 production. This is the first evidence that MC can regulate ASM cell CXCL10 production and its degradation. Thus MC may regulate airway myositis in asthma. PMID:24648846

  6. T-bet is induced by interferon-γ to mediate chemokine secretion and migration in human airway smooth muscle cells

    PubMed Central

    2011-01-01

    An inappropriate balance between T-helper (Th)1 and Th2 cytokine production underlies inflammatory changes that result in airway disease. Expression of the T-box transcription factor T-bet regulates differentiation of Th cells and production of Th1 cytokines, particularly IFNγ. T-bet-deficient mice develop airway hyperreactivity, undergo airway remodeling, and exhibit defects in IFNγ production while overproducing Th2 cytokines. T-bet is also reduced in the airways of asthmatic patients, suggesting loss of T-bet expression or activity promotes development of inflammatory airway disease. We present novel data demonstrating T-bet expression is induced in human airway smooth muscle cells (ASMC) by IFNγ. This IFNγ-stimulated expression of T-bet is dependent on signaling through JAK2 and signal transducers and activators of transcription 1 (STAT1) and activates T-bet-dependent DNA binding activity. Expression of T-bet stimulates IFNγ-stimulated IFNγ expression, secretion, and promoter activity, while inhibiting IFNγ-stimulated release of chemokines including monocyte chemoattractant protein (MCP)-1/CCL2, regulated on activation normal T-expressed and secreted (RANTES)/CCL5, and eotaxin/CCL11. This is accompanied by changes in expression of the chemokine receptors CCR3 and IL12Rβ2 and TNFα. T-bet expression also reduces chemotactic migration of ASMC in response to serum and PDGF, which contributes to airway hyperplasia. These results are the first to identify T-bet expression and activity in a structural cell of the lung and may provide new insights into therapeutic targets for inflammatory airway disease. PMID:21239533

  7. Sensorimotor function of the upper-airway muscles and respiratory sensory processing in untreated obstructive sleep apnea.

    PubMed

    Eckert, Danny J; Lo, Yu L; Saboisky, Julian P; Jordan, Amy S; White, David P; Malhotra, Atul

    2011-12-01

    Numerous studies have demonstrated upper-airway neuromuscular abnormalities during wakefulness in snorers and obstructive sleep apnea (OSA) patients. However, the functional role of sensorimotor impairment in OSA pathogenesis/disease progression and its potential effects on protective upper-airway reflexes, measures of respiratory sensory processing, and force characteristics remain unclear. This study aimed to gain physiological insight into the potential role of sensorimotor impairment in OSA pathogenesis/disease progression by comparing sensory processing properties (respiratory-related evoked potentials; RREP), functionally important protective reflexes (genioglossus and tensor palatini) across a range of negative pressures (brief pulses and entrained iron lung ventilation), and tongue force and time to task failure characteristics between 12 untreated OSA patients and 13 controls. We hypothesized that abnormalities in these measures would be present in OSA patients. Upper-airway reflexes (e.g., genioglossus onset latency, 20 ± 1 vs. 19 ± 2 ms, P = 0.82), early RREP components (e.g., P1 latency 25 ± 2 vs. 25 ± 1 ms, P = 0.78), and the slope of epiglottic pressure vs. genioglossus activity during iron lung ventilation (-0.68 ± 1.0 vs. -0.80 ± 2.0 cmH(2)O/%max, P = 0.59) were not different between patients and controls. Maximal tongue protrusion force was greater in OSA patients vs. controls (35 ± 2 vs. 27 ± 2 N, P < 0.01), but task failure occurred more rapidly (149 ± 24 vs. 254 ± 23 s, P < 0.01). Upper-airway protective reflexes across a range of negative pressures as measured by electromyography and the early P1 component of the RREP are preserved in OSA patients during wakefulness. Consistent with an adaptive training effect, tongue protrusion force is increased, not decreased, in untreated OSA patients. However, OSA patients may be vulnerable to fatigue of upper-airway dilator muscles, which could contribute to disease progression. PMID:21885797

  8. Effects of acute ethanol exposure on cytokine production by primary airway smooth muscle cells.

    PubMed

    Kaphalia, Lata; Kalita, Mridul; Kaphalia, Bhupendra S; Calhoun, William J

    2016-02-01

    Both chronic and binge alcohol abuse can be significant risk factors for inflammatory lung diseases such as acute respiratory distress syndrome and chronic obstructive pulmonary disease. However, metabolic basis of alcohol-related lung disease is not well defined, and may include key metabolites of ethanol [EtOH] in addition to EtOH itself. Therefore, we investigated the effects of EtOH, acetaldehyde [ACE], and fatty acid ethyl esters [FAEEs] on oxidative stress, endoplasmic reticulum (ER) stress, AMP-activated protein kinase (AMPK) signaling and nuclear translocation of phosphorylated (p)-NF-κB p65 in primary human airway smooth muscle (HASM) cells stimulated to produce cytokines using LPS exposure. Both FAEEs and ACE induced evidence of cellular oxidative stress and ER stress, and increased p-NF-κB in nuclear extracts. EtOH and its metabolites decreased p-AMPKα activation, and induced expression of fatty acid synthase, and decreased expression of sirtuin 1. In general, EtOH decreased secretion of IP-10, IL-6, eotaxin, GCSF, and MCP-1. However, FAEEs and ACE increased these cytokines, suggesting that both FAEEs and ACE as compared to EtOH itself are proinflammatory. A direct effect of EtOH could be consistent with blunted immune response. Collectively, these two features of EtOH exposure, coupled with the known inhibition of innate immune response in our model might explain some clinical manifestations of EtOH exposure in the lung. PMID:26721307

  9. Regulation of airway contractility by plasminogen activators through N-methyl-D-aspartate receptor-1.

    PubMed

    Nassar, Taher; Yarovoi, Serge; Fanne, Rami Abu; Akkawi, Sa'ed; Jammal, Mahmud; Allen, Timothy Craig; Idell, Steven; Cines, Douglas B; Higazi, Abd Al-Roof

    2010-12-01

    Reactive airway disease is mediated by smooth muscle contraction initiated through several agonist-dependent pathways. Activation of type 1 N-methyl-D-aspartate receptors (NMDA-R1s) by plasminogen activators (PAs) has been linked to control of vascular tone, but their effect on airway smooth muscle contractility has not previously been studied to our knowledge. We observed that NMDA-R1s are expressed by human airway smooth muscle cells and constitutively inhibit the contraction of isolated rat tracheal rings in response to acetylcholine (Ach). Both tissue-type PA (tPA) and urokinase-type PA (uPA) bind to NMDA-R1 and reverse this effect, thereby enhancing Ach-induced tracheal contractility. Tracheal contractility initiated by Ach is reduced in rings isolated from tPA(-/-) and uPA(-/-) mice compared with their wild-type counterparts. The procontractile effect of uPA or tPA was mimicked and augmented by the nitric oxide synthase inhibitor, l-NAME. uPA and tPA further enhanced the contractility of rings denuded of epithelium, an effect that was inhibited by the NMDA-R antagonist, MK-801. Binding of PAs to NMDA-R1 and the subsequent activation of the receptor were inhibited by PA inhibitor type 1, by a PA inhibitor type 1-derived hexapeptide that recognizes the tPA and uPA docking domains, as well as by specific mutations within the docking site of tPA. These studies identify involvement of PAs and NMDA-R1 in airway contractility, and define new loci that could lead to the development of novel interventions for reactive airway disease. PMID:20097831

  10. Spatial and temporal traction response in human airway smooth muscle cells

    NASA Technical Reports Server (NTRS)

    Tolic-Norrelykke, Iva Marija; Butler, James P.; Chen, Jianxin; Wang, Ning

    2002-01-01

    Tractions that cells exert on their substrates are essential in cell spreading, migration, and contraction. These tractions can be determined by plating the cells on a flexible gel and measuring the deformation of the gel by using fluorescent beads embedded just below the surface of the gel. In this article we describe the image correlation method (ICM) optimized for determining the displacement field of the gel under a contracting cell. For the calculation of the traction field from the displacement field we use the recently developed method of Fourier transform traction cytometry (FTTC). The ICM and FTTC methods are applied to human airway smooth muscle cells during stimulation with the contractile agonist histamine or the relaxing agonist isoproterenol. The overall intensity of the cell contraction (the median traction magnitude, the energy transferred from the cell to the gel, and the net contractile moment) increased after activation with histamine, and decreased after treatment with isoproterenol. Cells exhibited regional differences in the time course of traction during the treatment. Both temporal evolution and magnitude of traction increase induced by histamine varied markedly among different cell protrusions, whereas the nuclear region showed the smallest response. These results suggest that intracellular mediators of cell adhesion and contraction respond to contractile stimuli with different rates and intensities in different regions of the cell.

  11. Reactive oxygen species induce a Ca(2+)-spark increase in sensitized murine airway smooth muscle cells.

    PubMed

    Tuo, Qing-Rong; Ma, Yun-Fei; Chen, Weiwei; Luo, Xiao-Jing; Shen, Jinhua; Guo, Donglin; Zheng, Yun-Min; Wang, Yong-Xiao; Ji, Guangju; Liu, Qing-Hua

    2013-05-10

    The level of reactive oxygen species (ROS) and the activity of spontaneous, transient, localized Ca(2+) increases (known as Ca(2+) sparks) in tracheal smooth muscle cells (TSMCs) in an experimental allergic asthma mouse model has not yet been investigated. We used laser confocal microscopy and fluorescent dyes to measure ROS levels and Ca(2+) sparks, and we found that both events were significantly increased in TSMCs obtained from ovalbumin (OVA)-sensitized/-challenged mice compared with control mice. ROS levels began to increase in TSMCs after the first OVA challenge, and this increase was sustained. However, this elevation and Ca(2+)-spark increase was abolished after the administration of the ROS scavenger N-acetylcysteine amide (NACA) for 5days. Furthermore, a similar inhibition was also observed following the direct perfusion of NACA into cells isolated from the (OVA)-sensitized mice that were not treated with NACA. Moreover, we used 0.1-mM caffeine treatment to increase the Ca(2+) sparks in single TSMCs and observed cell shortening. In addition, we did not find increases in the mRNA levels of ryanodine (RyRs) and inositol 1,4,5-trisphosphate (IP3Rs) receptors in the tracheal smooth muscle cells of (OVA)-sensitized mice compared with controls. We concluded that ROS and Ca(2+) sparks increased in (OVA)-sensitized TSMCs. We found that ROS induces Ca(2+) sparks, and increased Ca(2+) sparks resulted in the contraction of (OVA)-sensitized TSMCs, resulting in the generation of airway hyperresponsiveness (AHR). This effect may represent a novel mechanism for AHR pathogenesis and might provide insight into new methods for the clinical prevention and treatment of asthma and asthmatic AHR. PMID:23583396

  12. The effects of cannabidiol on the antigen-induced contraction of airways smooth muscle in the guinea-pig.

    PubMed

    Dudášová, A; Keir, S D; Parsons, M E; Molleman, A; Page, C P

    2013-06-01

    (-)-Δ(9)-Tetrahydrocannabinol has been demonstrated to have beneficial effects in the airways, but its psychoactive effects preclude its therapeutic use for the treatment of airways diseases. In the present study we have investigated the effects of (-)-cannabidiol, a non-psychoactive component of cannabis for its actions on bronchial smooth muscle in vitro and in vivo. Guinea-pig bronchial smooth muscle contractions induced by exogenously applied spasmogens were measured isometrically. In addition, contractile responses of bronchial smooth muscle from ovalbumin-sensitized guinea-pigs were investigated in the absence or presence of (-)-cannabidiol. Furthermore, the effect of (-)-cannabidiol against ovalbumin-induced airway obstruction was investigated in vivo in ovalbumin-sensitized guinea-pigs. (-)-Cannabidiol did not influence the bronchial smooth muscle contraction induced by carbachol, histamine or neurokinin A. In contrast, (-)-cannabidiol inhibited anandamide- and virodhamine-induced responses of isolated bronchi. A fatty acid amide hydrolase inhibitor, phenylmethanesulfonyl fluoride reversed the inhibitory effect of (-)-cannabidiol on anandamide-induced contractions. In addition, (-)-cannabidiol inhibited the contractile response of bronchi obtained from allergic guinea-pigs induced by ovalbumin. In vivo, (-)-cannabidiol reduced ovalbumin-induced airway obstruction. In conclusion, our results suggest that cannabidiol can influence antigen-induced airway smooth muscle tone suggesting that this molecule may have beneficial effects in the treatment of obstructive airway disorders. PMID:23428645

  13. Nuclear factor-κB mediates the phenotype switching of airway smooth muscle cells in a murine asthma model

    PubMed Central

    Qiu, Chen; Zhang, Jian; Su, Meiping; Fan, Xiujun

    2015-01-01

    Airway smooth muscle cells (ASMCs) phenotype modulation, characterized by reversible switching between contractile and proliferative phenotypes, is considered to contribute to airway proliferative diseases such as allergic asthma. Nuclear Factor-κB (NF-κB) has been reported as a key regulator for the occurrence and development of asthma. However, little is known regarding its role in ASM cell phenotypic modulation. To elucidate the role of NF-κB in regulating ASM cells phenotypic modulation, we investigated the effects of NF-κB on ASM cells contractile marker protein expression, and its impact on proliferation and apoptosis. We found that chronic asthma increased the activation of NF-κB in the primary murine ASM cells with a concomitant marked decrease in the expression of contractile phenotypic marker protein including smooth muscle alpha-actin (α-SMA). Additionally, we used the normal ASM cells under different processing to build the phenotype switching when we found the activation of NF-κB. Meanwhile, the expression of α-SMA in asthma was significantly increased by the NF-κB blocker. NF-κB blocker also suppressed asthma mouse ASM cell proliferation and promoted apoptosis. These findings highlight a novel role for the NF-κB in murine ASM cell phenotypic modulation and provide a potential target for therapeutic intervention for asthma. PMID:26722396

  14. Endobronchial Ultrasound Reliably Quantifies Airway Smooth Muscle Remodeling in an Equine Asthma Model.

    PubMed

    Bullone, Michela; Beauchamp, Guy; Godbout, Mireille; Martin, James G; Lavoie, Jean-Pierre

    2015-01-01

    Endobronchial ultrasonography (EBUS) revealed differences in the thickness of the layer representing subepithelial tissues (L2) between human asthmatics and controls, but whether this measurement correlates with airway smooth muscle (ASM) remodeling in asthma is unknown. In this study, we sought to determine the ability of EBUS to predict histological ASM remodeling in normal and equine asthmatic airways. We studied 109 isolated bronchi from the lungs of 13 horses. They underwent EBUS examination using a 30 MHz radial probe before being processed for histology. ASM remodeling parameters were evaluated in EBUS images (L2 thickness, L2 area, L2 area/internal perimeter [Pi] and L2 area/Pi2) and histological cuts (ASM area/Pi2), and compared. EBUS was then performed ex vivo on the lungs of 4 horses with heaves, an asthma-like condition of horses, and 7 controls to determine whether central bronchial remodeling could be detected with this technique. An optimized approach was developed based on data variability within airways, subjects, and groups, and then validated in 7 horses (3 controls, 4 with heaves) that underwent EBUS in vivo. L2 area was significantly associated to ASM area in isolated lungs (p<0.0001), in the absence of significant bias related to the airway size. Bronchial size significantly affected EBUS ASM-related parameters, except for L2 area/Pi2. L2 area/Pi2 was increased in the airways of asthmatic horses compared to controls, both ex vivo and in vivo (p<0.05). Bronchial histology confirmed our findings (AASM/Pi2 was increased in asthmatic horses compared to controls, p<0.05). In both horses with heaves and controls, L2 was composed of ASM for the outer 75% of its thickness and by ECM for the remaining inner 25%. In conclusion, EBUS reliably allows assessment of asthma-associated ASM remodeling of central airways in a non-invasive way. PMID:26348727

  15. Endobronchial Ultrasound Reliably Quantifies Airway Smooth Muscle Remodeling in an Equine Asthma Model

    PubMed Central

    Bullone, Michela; Beauchamp, Guy; Godbout, Mireille; Martin, James G.; Lavoie, Jean-Pierre

    2015-01-01

    Endobronchial ultrasonography (EBUS) revealed differences in the thickness of the layer representing subepithelial tissues (L2) between human asthmatics and controls, but whether this measurement correlates with airway smooth muscle (ASM) remodeling in asthma is unknown. In this study, we sought to determine the ability of EBUS to predict histological ASM remodeling in normal and equine asthmatic airways. We studied 109 isolated bronchi from the lungs of 13 horses. They underwent EBUS examination using a 30 MHz radial probe before being processed for histology. ASM remodeling parameters were evaluated in EBUS images (L2 thickness, L2 area, L2 area/internal perimeter [Pi] and L2 area/Pi2) and histological cuts (ASM area/Pi2), and compared. EBUS was then performed ex vivo on the lungs of 4 horses with heaves, an asthma-like condition of horses, and 7 controls to determine whether central bronchial remodeling could be detected with this technique. An optimized approach was developed based on data variability within airways, subjects, and groups, and then validated in 7 horses (3 controls, 4 with heaves) that underwent EBUS in vivo. L2 area was significantly associated to ASM area in isolated lungs (p<0.0001), in the absence of significant bias related to the airway size. Bronchial size significantly affected EBUS ASM-related parameters, except for L2 area/Pi2. L2 area/Pi2 was increased in the airways of asthmatic horses compared to controls, both ex vivo and in vivo (p<0.05). Bronchial histology confirmed our findings (AASM/Pi2 was increased in asthmatic horses compared to controls, p<0.05). In both horses with heaves and controls, L2 was composed of ASM for the outer 75% of its thickness and by ECM for the remaining inner 25%. In conclusion, EBUS reliably allows assessment of asthma-associated ASM remodeling of central airways in a non-invasive way. PMID:26348727

  16. Fetal human airway smooth muscle cell production of leukocyte chemoattractants is differentially regulated by fluticasone

    PubMed Central

    Pearson, Helen; Britt, Rodney D.; Pabelick, Christine M.; Prakash, Y.S.; Amrani, Yassine; Pandya, Hitesh C.

    2016-01-01

    Background Adult human airway smooth muscle (ASM) produce cytokines involved in recruitment and survival of leukocytes within airway walls. Cytokine generation by adult ASM is glucocorticoid-sensitive. Whether developing lung ASM produces cytokines in a glucocorticoid-sensitive fashion is unknown. Methods Cultured fetal human ASM cells stimulated with TNF-α (0–20 ng/ml) were incubated with TNF-α receptor-blocking antibodies, fluticasone (1 and 100 nm), or vehicle. Supernatants and cells were assayed for the production of CCL5, CXCL10, and CXCL8 mRNA and protein and glucocorticoid receptor phosphorylation. Results CCL5, CXCL10, and CXCL8 mRNA and protein production by fetal ASM cell was significantly and dose-dependently following TNF-α treatment. Cytokine mRNA and protein production were effectively blocked by TNF-α R1 and R2 receptor neutralizing antibodies but variably inhibited by fluticasone. TNF-α-induced TNF-R1 and R2 receptor mRNA expression was only partially attenuated by fluticasone. Glucocorticoid receptor phosphorylation at serine (Ser) 211 but not at Ser 226 was enhanced by fluticasone. Conclusion Production of CCL5, CXCL10, and CXCL8 by fetal ASM appears to involve pathways that are both qualitatively and mechanistically distinct to those described for adult ASM. The findings imply developing ASM has potential to recruit leukocyte into airways and, therefore, of relevance to childhood airway diseases. PMID:26331770

  17. Upper Airway Collapsibility and Genioglossus Activity in Adolescents during Sleep

    PubMed Central

    Huang, Jingtao; Pinto, Swaroop J.; Yuan, Haibo; Katz, Eliot S.; Karamessinis, Laurie R.; Bradford, Ruth M.; Gallagher, Paul R.; Hannigan, James T.; Nixon, Thomas; Ward, Michelle B.; Lee, Yin N.; Marcus, Carole L.

    2012-01-01

    Study Objectives: Obese patients develop obstructive sleep apnea syndrome (OSAS), at least in part because of a narrowed upper airway. However, many obese adolescents do not develop OSAS, despite having a presumably narrower airway. The reasons for this phenomenon are unclear. The authors hypothesized that obese controls have a compensatory neuromuscular response to subatmospheric pressure loads during sleep, making them less likely to develop upper airway collapse. Design: Patients underwent pressure-flow measurements during sleep while wearing intraoral electrodes to measure genioglossal electromyography (EMGgg). Two techniques were applied to decrease nasal pressure (PN) to subatmospheric levels, resulting in an activated and relatively hypotonic upper airway. Setting: Sleep laboratory. Participants: There were 35 obese patients with OSAS, 28 obese controls, and 43 lean controls. Results: In the activated state, the two control groups had a flatter slope of the pressure-flow relationship and a more negative critical closing pressure (less collapsible) than the OSAS group. In the hypotonic state, the lean controls had a flatter slope of the pressure-flow relationship than the OSAS and obese control groups. In the activated state, the slope of EMGgg versus PN was greater in the obese control group than in the OSAS or lean control groups (P = 0.002 and P = 0.028, respectively); there were no differences in the hypotonic state. Conclusions: Obese controls have vigorous upper airway neuromuscular responses during sleep. Upper airway reflexes normally decline during adolescent development. It is speculated that obese adolescents without OSAS maintain protective upper airway reflexes during adolescent development, whereas those who go on to develop OSAS do not. Citation: Huang J; Pinto SJ; Yuan H; Katz ES; Karamessinis LR; Bradford RM; Gallagher PR; Hannigan JT; Nixon T; Ward MB; Lee YN; Marcus CL. Upper airway collapsibility and genioglossus activity in adolescents

  18. Triptolide inhibits TGF-β1-induced cell proliferation in rat airway smooth muscle cells by suppressing Smad signaling

    SciTech Connect

    Chen, Ming; Lv, Zhiqiang; Huang, Linjie; Zhang, Wei; Lin, Xiaoling; Shi, Jianting; Zhang, Wei; Liang, Ruiyun; Jiang, Shanping

    2015-02-15

    Background: We have reported that triptolide can inhibit airway remodeling in a murine model of asthma via TGF-β1/Smad signaling. In the present study, we aimed to investigate the effect of triptolide on airway smooth muscle cells (ASMCs) proliferation and the possible mechanism. Methods: Rat airway smooth muscle cells were cultured and made synchronized, then pretreated with different concentration of triptolide before stimulated by TGF-β1. Cell proliferation was evaluated by MTT assay. Flow cytometry was used to study the influence of triptolide on cell cycle and apoptosis. Signal proteins (Smad2, Smad3 and Smad7) were detected by western blotting analysis. Results: Triptolide significantly inhibited TGF-β1-induced ASMC proliferation (P<0.05). The cell cycle was blocked at G1/S-interphase by triptolide dose dependently. No pro-apoptotic effects were detected under the concentration of triptolide we used. Western blotting analysis showed TGF-β1 induced Smad2 and Smad3 phosphorylation was inhibited by triptolide pretreatment, and the level of Smad7 was increased by triptolide pretreatment. Conclusions: Triptolide may function as an inhibitor of asthma airway remodeling by suppressing ASMCs proliferation via negative regulation of Smad signaling pathway. - Highlights: • In this study, rat airway smooth muscle cells were cultured and made synchronized. • Triptolide inhibited TGF-β1-induced airway smooth muscle cells proliferation. • Triptolide inhibited ASMCs proliferation via negative regulation of Smad signaling pathway.

  19. IgE induces proliferation in human airway smooth muscle cells: role of MAPK and STAT3 pathways.

    PubMed

    Redhu, Naresh Singh; Shan, Lianyu; Al-Subait, Duaa; Ashdown, Heather L; Movassagh, Hesam; Lamkhioued, Bouchaib; Gounni, Abdelilah S

    2013-01-01

    Airway remodeling is not specifically targeted by current asthma medications, partly owing to the lack of understanding of remodeling mechanisms, altogether posing great challenges in asthma treatment. Increased airway smooth muscle (ASM) mass due to hyperplasia/hypertrophy contributes significantly to overall airway remodeling and correlates with decline in lung function. Recent evidence suggests that IgE sensitization can enhance the survival and mediator release in inflammatory cells. Human ASM (HASM) cells express both low affinity (FcεRII/CD23) and high affinity IgE Fc receptors (FcεRI), and IgE can modulate the contractile and synthetic function of HASM cells. IgE was recently shown to induce HASM cell proliferation but the detailed mechanisms remain unknown. We report here that IgE sensitization induces HASM cell proliferation, as measured by 3H-thymidine, EdU incorporation, and manual cell counting. As an upstream signature component of FcεRI signaling, inhibition of spleen tyrosine kinase (Syk) abrogated the IgE-induced HASM proliferation. Further analysis of IgE-induced signaling depicted an IgE-mediated activation of Erk 1/2, p38, JNK MAPK, and Akt kinases. Lastly, lentiviral-shRNA-mediated STAT3 silencing completely abolished the IgE-mediated HASM cell proliferation. Collectively, our data provide mechanisms of a novel function of IgE which may contribute, at least in part, to airway remodeling observed in allergic asthma by directly inducing HASM cell proliferation. PMID:24499258

  20. Sex Steroids Influence Brain-Derived Neurotropic Factor Secretion From Human Airway Smooth Muscle Cells.

    PubMed

    Wang, Sheng-Yu; Freeman, Michelle R; Sathish, Venkatachalem; Thompson, Michael A; Pabelick, Christina M; Prakash, Y S

    2016-07-01

    Brain derived neurotropic factor (BDNF) is emerging as an important player in airway inflammation, remodeling, and hyperreactivity. Separately, there is increasing evidence that sex hormones contribute to pathophysiology in the lung. BDNF and sex steroid signaling are thought to be intricately linked in the brain. There is currently little information on BDNF and sex steroid interactions in the airway but is relevant to understanding growth factor signaling in the context of asthma in men versus women. In this study, we assessed the effect of sex steroids on BDNF expression and secretion in human airway smooth muscle (ASM). Human ASM was treated with estrogen (E2 ) or testosterone (T, 10 nM each) and intracellular BDNF and secreted BDNF measured. E2 and T significantly reduced secretion of BDNF; effects prevented by estrogen and androgen receptor inhibitor, ICI 182,780 (1 μM), and flutamide (10 μM), respectively. Interestingly, no significant changes were observed in intracellular BDNF mRNA or protein expression. High affinity BDNF receptor, TrkB, was not altered by E2 or T. E2 (but not T) significantly increased intracellular cyclic AMP levels. Notably, Epac1 and Epac2 expression were significantly reduced by E2 and T. Furthermore, SNARE complex protein SNAP25 was decreased. Overall, these novel data suggest that physiologically relevant concentrations of E2 or T inhibit BDNF secretion in human ASM, suggesting a potential interaction of sex steroids with BDNF in the airway that is different from brain. The relevance of sex steroid-BDNF interactions may lie in their overall contribution to airway diseases such as asthma. J. Cell. Physiol. 231: 1586-1592, 2016. © 2015 Wiley Periodicals, Inc. PMID:26566264

  1. The effects of in utero vitamin D deficiency on airway smooth muscle mass and lung function.

    PubMed

    Foong, Rachel E; Bosco, Anthony; Jones, Anya C; Gout, Alex; Gorman, Shelley; Hart, Prue H; Zosky, Graeme R

    2015-11-01

    We have previously demonstrated increased airway smooth muscle (ASM) mass and airway hyperresponsiveness in whole-life vitamin D-deficient female mice. In this study, we aimed to uncover the molecular mechanisms contributing to altered lung structure and function. RNA was extracted from lung tissue of whole-life vitamin D-deficient and -replete female mice, and gene expression patterns were profiled by RNA sequencing. The data showed that genes involved in embryonic organ development, pattern formation, branching morphogenesis, Wingless/Int signaling, and inflammation were differentially expressed in vitamin D-deficient mice. Network analysis suggested that differentially expressed genes were connected by the hubs matrix metallopeptidase 9; NF-κ light polypeptide gene enhancer in B cells inhibitor, α; epidermal growth factor receptor; and E1A binding protein p300. Given our findings that developmental pathways may be altered, we investigated if the timing of vitamin D exposure (in utero vs. postnatal) had an impact on lung health outcomes. Gene expression was measured in in utero or postnatal vitamin D-deficient mice, as well as whole-life vitamin D-deficient and -replete mice at 8 weeks of age. Baseline lung function, airway hyperresponsiveness, and airway inflammation were measured and lungs fixed for lung structure assessment using stereological methods and quantification of ASM mass. In utero vitamin D deficiency was sufficient to increase ASM mass and baseline airway resistance and alter lung structure. There were increased neutrophils but decreased lymphocytes in bronchoalveolar lavage. Expression of inflammatory molecules S100A9 and S100A8 was mainly increased in postnatal vitamin D-deficient mice. These observations suggest that in utero vitamin D deficiency can alter lung structure and function and increase inflammation, contributing to symptoms in chronic diseases, such as asthma. PMID:25867172

  2. A-kinase-anchoring proteins coordinate inflammatory responses to cigarette smoke in airway smooth muscle

    PubMed Central

    Heijink, Irene H.; Holtzer, Laura J.; Skroblin, Philipp; Klussmann, Enno; Halayko, Andrew J.; Timens, Wim; Maarsingh, Harm; Schmidt, Martina

    2015-01-01

    β2-Agonist inhibitors can relieve chronic obstructive pulmonary disease (COPD) symptoms by stimulating cyclic AMP (cAMP) signaling. A-kinase-anchoring proteins (AKAPs) compartmentalize cAMP signaling by establishing protein complexes. We previously reported that the β2-agonist fenoterol, direct activation of protein kinase A (PKA), and exchange factor directly activated by cAMP decrease cigarette smoke extract (CSE)-induced release of neutrophil attractant interleukin-8 (IL-8) from human airway smooth muscle (ASM) cells. In the present study, we tested the role of AKAPs in CSE-induced IL-8 release from ASM cells and assessed the effect of CSE on the expression levels of different AKAPs. We also studied mRNA and protein expression of AKAPs in lung tissue from patients with COPD. Our data show that CSE exposure of ASM cells decreases AKAP5 and AKAP12, both capable of interacting with β2-adrenoceptors. In lung tissue of patients with COPD, mRNA levels of AKAP5 and AKAP12 were decreased compared with lung tissue from controls. Using immunohistochemistry, we detected less AKAP5 protein in ASM of patients with COPD Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage II compared with control subjects. St-Ht31, which disrupts AKAP-PKA interactions, augmented CSE-induced IL-8 release from ASM cells and diminished its suppression by fenoterol, an effect mediated by disturbed ERK signaling. The modulatory role of AKAP-PKA interactions in the anti-inflammatory effects of fenoterol in ASM cells and the decrease in expression of AKAP5 and AKAP12 in response to cigarette smoke and in lungs of patients with COPD suggest that cigarette smoke-induced changes in AKAP5 and AKAP12 in patients with COPD may affect efficacy of pharmacotherapy. PMID:25637608

  3. A-kinase-anchoring proteins coordinate inflammatory responses to cigarette smoke in airway smooth muscle.

    PubMed

    Poppinga, Wilfred J; Heijink, Irene H; Holtzer, Laura J; Skroblin, Philipp; Klussmann, Enno; Halayko, Andrew J; Timens, Wim; Maarsingh, Harm; Schmidt, Martina

    2015-04-15

    β2-Agonist inhibitors can relieve chronic obstructive pulmonary disease (COPD) symptoms by stimulating cyclic AMP (cAMP) signaling. A-kinase-anchoring proteins (AKAPs) compartmentalize cAMP signaling by establishing protein complexes. We previously reported that the β2-agonist fenoterol, direct activation of protein kinase A (PKA), and exchange factor directly activated by cAMP decrease cigarette smoke extract (CSE)-induced release of neutrophil attractant interleukin-8 (IL-8) from human airway smooth muscle (ASM) cells. In the present study, we tested the role of AKAPs in CSE-induced IL-8 release from ASM cells and assessed the effect of CSE on the expression levels of different AKAPs. We also studied mRNA and protein expression of AKAPs in lung tissue from patients with COPD. Our data show that CSE exposure of ASM cells decreases AKAP5 and AKAP12, both capable of interacting with β2-adrenoceptors. In lung tissue of patients with COPD, mRNA levels of AKAP5 and AKAP12 were decreased compared with lung tissue from controls. Using immunohistochemistry, we detected less AKAP5 protein in ASM of patients with COPD Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage II compared with control subjects. St-Ht31, which disrupts AKAP-PKA interactions, augmented CSE-induced IL-8 release from ASM cells and diminished its suppression by fenoterol, an effect mediated by disturbed ERK signaling. The modulatory role of AKAP-PKA interactions in the anti-inflammatory effects of fenoterol in ASM cells and the decrease in expression of AKAP5 and AKAP12 in response to cigarette smoke and in lungs of patients with COPD suggest that cigarette smoke-induced changes in AKAP5 and AKAP12 in patients with COPD may affect efficacy of pharmacotherapy. PMID:25637608

  4. Steroids and antihistamines synergize to inhibit rat's airway smooth muscle contractility.

    PubMed

    Liu, Shao-Cheng; Chu, Yueng-Hsiang; Kao, Chuan-Hsiang; Wu, Chi-Chung; Wang, Hsing-Won

    2015-06-01

    Both glucocorticoids and H1-antihistamines were widely used on patients with allergic rhinitis (AR) and obstructive airway diseases. However, their direct effects on airway smooth muscle were not fully explored. In this study, we tested the effectiveness of prednisolone (Kidsolone) and levocetirizine (Xyzal) on isolated rat trachea submersed in Kreb's solution in a muscle bath. Changes in tracheal contractility in response to the application of parasympathetic mimetic agents were measured. The following assessments of the drug were performed: (1) effect on tracheal smooth muscle resting tension; (2) effect on contraction caused by 10(-6) M methacholine; (3) effect of the drug on electrical field stimulation (EFS) induced tracheal smooth muscle contractions. The result revealed sole use of Kidsolone or Xyzal elicited no significant effect or only a little relaxation response on tracheal tension after methacholine treatment. The tension was 90.5 ± 7.5 and 99.5 ± 0.8 % at 10(-4) M for Xyzal and 10(-5) M for Kidsolone, respectively. However, a dramatically spasmolytic effect was observed after co-administration of Kidsolone and Xyzal and the tension dropped to 67.5 ± 13.6 %, with statistical significance (p < 0.05). As for EFS-induced contractions, Kidsolone had no direct effect but Xyzal could inhibit it, with increasing basal tension. In conclusion, using glucocorticoids alone had no spasmolytic effect but they can be synergized with antihistamines to dramatically relax the trachea smooth muscle within minutes. Therefore, for AR patients with acute asthma attack, combined use of those two drugs is recommended. PMID:25115316

  5. Vitamin D Modulates Expression of the Airway Smooth Muscle Transcriptome in Fatal Asthma

    PubMed Central

    Johnson, Martin; Nikolos, Christina; Jester, William; Klanderman, Barbara; Litonjua, Augusto A.; Tantisira, Kelan G.; Truskowski, Kevin; MacDonald, Kevin; Panettieri, Reynold A.; Weiss, Scott T.

    2015-01-01

    Globally, asthma is a chronic inflammatory respiratory disease affecting over 300 million people. Some asthma patients remain poorly controlled by conventional therapies and experience more life-threatening exacerbations. Vitamin D, as an adjunct therapy, may improve disease control in severe asthma patients since vitamin D enhances glucocorticoid responsiveness and mitigates airway smooth muscle (ASM) hyperplasia. We sought to characterize differences in transcriptome responsiveness to vitamin D between fatal asthma- and non-asthma-derived ASM by using RNA-Seq to measure ASM transcript expression in five donors with fatal asthma and ten non-asthma-derived donors at baseline and with vitamin D treatment. Based on a Benjamini-Hochberg corrected p-value <0.05, 838 genes were differentially expressed in fatal asthma vs. non-asthma-derived ASM at baseline, and vitamin D treatment compared to baseline conditions induced differential expression of 711 and 867 genes in fatal asthma- and non-asthma-derived ASM, respectively. Functional gene categories that were highly represented in all groups included extracellular matrix, and responses to steroid hormone stimuli and wounding. Genes differentially expressed by vitamin D also included cytokine and chemokine activity categories. Follow-up qPCR and individual analyte ELISA experiments were conducted for four cytokines (i.e. CCL2, CCL13, CXCL12, IL8) to measure TNFα-induced changes by asthma status and vitamin D treatment. Vitamin D inhibited TNFα-induced IL8 protein secretion levels to a comparable degree in fatal asthma- and non-asthma-derived ASM even though IL8 had significantly higher baseline levels in fatal asthma-derived ASM. Our findings identify vitamin D-specific gene targets and provide transcriptomic data to explore differences in the ASM of fatal asthma- and non-asthma-derived donors. PMID:26207385

  6. Myosin filament polymerization and depolymerization in a model of partial length adaptation in airway smooth muscle.

    PubMed

    Ijpma, Gijs; Al-Jumaily, Ahmed M; Cairns, Simeon P; Sieck, Gary C

    2011-09-01

    Length adaptation in airway smooth muscle (ASM) is attributed to reorganization of the cytoskeleton, and in particular the contractile elements. However, a constantly changing lung volume with tidal breathing (hence changing ASM length) is likely to restrict full adaptation of ASM for force generation. There is likely to be continuous length adaptation of ASM between states of incomplete or partial length adaption. We propose a new model that assimilates findings on myosin filament polymerization/depolymerization, partial length adaptation, isometric force, and shortening velocity to describe this continuous length adaptation process. In this model, the ASM adapts to an optimal force-generating capacity in a repeating cycle of events. Initially the myosin filament, shortened by prior length changes, associates with two longer actin filaments. The actin filaments are located adjacent to the myosin filaments, such that all myosin heads overlap with actin to permit maximal cross-bridge cycling. Since in this model the actin filaments are usually longer than myosin filaments, the excess length of the actin filament is located randomly with respect to the myosin filament. Once activated, the myosin filament elongates by polymerization along the actin filaments, with the growth limited by the overlap of the actin filaments. During relaxation, the myosin filaments dissociate from the actin filaments, and then the cycle repeats. This process causes a gradual adaptation of force and instantaneous adaptation of shortening velocity. Good agreement is found between model simulations and the experimental data depicting the relationship between force development, myosin filament density, or shortening velocity and length. PMID:21659490

  7. Airway smooth muscle dysfunction precedes teratogenic congenital diaphragmatic hernia and may contribute to hypoplastic lung morphogenesis.

    PubMed

    Featherstone, Neil C; Connell, Marilyn G; Fernig, David G; Wray, Susan; Burdyga, Theodor V; Losty, Paul D; Jesudason, Edwin C

    2006-11-01

    Fetal intervention aims to improve lung growth and survival in congenital diaphragmatic hernia (CDH). Airway smooth muscle (ASM) is important in lung development: ASM progenitors produce a key growth factor for lung morphogenesis (fibroblast growth factor 10); ASM contractility is also coupled to growth. ASM hyperreactivity occurs in postnatal CDH and may exacerbate barotrauma via impaired lung compliance. We hypothesize that ASM hyperreactivity and its sequelae are based on an early developmental lesion of ASM activity in hypoplastic lung. Sprague-Dawley rats were fed 100 mg nitrofen on Day 9.5 of pregnancy to induce lung hypoplasia in offspring (controls had vehicle alone). Normal and hypoplastic lung primordia were cultured from Day 13.5 of gestation at 37 degrees C in 5% CO(2) and loaded at 54 or 78 h with Ca(2+)-sensitive indicators: Fluo-4 for confocal imaging and Indo-1 or Fura-2 for photometric measurements of [Ca(2+)](i). Hypoplastic lung features spontaneous propagating ASM Ca(2+) transients with reduced frequency, increased amplitude, and significantly prolonged plateau duration, relative to control lung. Nonetheless, hypoplastic lung exhibits normal requirement for extracellular calcium entry and intracellular calcium release in initiation and regulation of ASM Ca(2+) waves. Early ASM dysfunction in lung hypoplasia is apparent as specific anomalies of Ca(2+) transients that indicate a problem with plasmalemmal ion channels/action potential generation. Elucidation of such an ASM lesion may allow pharmacologic amelioration not only of ASM hyperreactivity and its sequelae, but also of hypoplastic lung growth itself. PMID:16728706

  8. Ovalbumin sensitization of guinea pig at birth prevents the ontogenetic decrease in airway smooth muscle responsiveness

    PubMed Central

    Chitano, Pasquale; Wang, Lu; Degan, Simone; Worthington, Charles L.; Pozzato, Valeria; Hussaini, Syed H.; Turner, Wesley C.; Dorscheid, Delbert R.; Murphy, Thomas M.

    2014-01-01

    Abstract Airway smooth muscle (ASM) displays a hyperresponsive phenotype at young age and becomes less responsive in adulthood. We hypothesized that allergic sensitization, which causes ASM hyperresponsiveness and typically occurs early in life, prevents the ontogenetic loss of the ASM hyperresponsive phenotype. We therefore studied whether neonatal allergic sensitization, not followed by later allergen challenges, alters the ontogenesis of ASM properties. We neonatally sensitized guinea pigs to ovalbumin and studied them at 1 week, 3 weeks, and 3 months (adult). A Schultz‐Dale response in isolated tracheal rings confirmed sensitization. The occurrence of inflammation was evaluated in the blood and in the submucosa of large airways. We assessed ASM function in tracheal strips as ability to produce force and shortening. ASM content of vimentin was also studied. A Schultz‐Dale response was observed in all 3‐week or older sensitized animals. A mild inflammatory process was characterized by eosinophilia in the blood and in the airway submucosa. Early life sensitization had no effect on ASM force generation, but prevented the ontogenetic decline of shortening velocity and the increase in resistance to shortening. Vimentin increased with age in control but not in sensitized animals. Allergic sensitization at birth without subsequent allergen exposures is sufficient to prevent normal ASM ontogenesis, inducing persistence to adulthood of an ASM hyperresponsive phenotype. PMID:25501429

  9. Studying airway smooth muscle in vivo with PS-OCT (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Adams, David C.; Hariri, Lida P.; Miller, Alyssa J.; Villiger, Martin; Holz, Jasmin; Szabari, Margit V.; Bouma, Brett E.; Luster, Andrew D.; Medoff, Benjamin D.; Suter, Melissa J.

    2016-03-01

    Present understanding of the pathophysiological mechanisms of asthma has been severely limited by the lack of an imaging modality capable of assessing airway conditions of asthma patients in vivo. Of particular interest is the role that airway smooth muscle (ASM) plays in the development of asthma and asthma related symptoms. We have developed novel techniques that we applied to Polarization Sensitive OCT (PS-OCT) in order to assess ASM, and validated our results with a substantial number of histological matches. In this work we employ our system in the study of ASM distributions in both asthmatic and non-asthmatic airways with data obtained in vivo from human volunteers. By isolating the ASM and performing volumetric analysis we obtain a variety of informative metrics such as ASM thickness and band width, and compare these quantities between subject types. Furthermore, we demonstrate that the degree of birefringence of the ASM can be associated with contractility, allowing us to estimate pressure exerted by ASM during contraction. We apply this technique to in vivo datasets from human volunteers as well.

  10. Effects of miRNA-145 on airway smooth muscle cells function.

    PubMed

    Liu, Yun; Sun, Xiuzhen; Wu, Yuanyuan; Fang, Ping; Shi, Hongyang; Xu, Jing; Li, Manxiang

    2015-11-01

    The pathological changes of airway smooth muscle (ASM) contribute to airway remodeling during asthma. Here, we investigated the effect of miR-145 on ASM function. We found that miR-145 was aberrantly more highly expressed in ASM cells exposed to cytokine stimulation that mimic the airway conditions of patients with asthma. Repression of miR-145 resulted in decreased ASM cell proliferation and migration in a dose-dependent manner and down-regulation of type I collagen and contractile protein MHC in ASM cells. qRT-PCR and Western blot analysis demonstrated that miR-145 negatively regulated the expression of downstream target Krüppel-like factor 4 (KLF4) protein, and overexpression of KLF4 attenuated the effects of miR-145 on ASM cells. Further studies showed that KLF4 significantly up-regulated the expression of p21 and down-regulated matrix metalloproteinase (MMP-2 and MMP-9). In conclusion, miR-145 overexpression in ASM cells significantly inhibited KLF4, and subsequently affected downstream p21, MMP-2, and MMP-9 expressions, eventually leading to enhanced proliferation and migration of ASM cells in vitro. PMID:26197891

  11. Human airway epithelia express catalytically active NEU3 sialidase

    PubMed Central

    Hyun, Sang Won; Feng, Chiguang; Zhang, Lei; Liu, Anguo; Guang, Wei; Nguyen, Chinh; Sun, Wenji; Luzina, Irina G.; Webb, Tonya J.; Atamas, Sergei P.; Passaniti, Antonino; Twaddell, William S.; Puché, Adam C.; Wang, Lai-Xi; Cross, Alan S.; Goldblum, Simeon E.

    2014-01-01

    Sialic acids on glycoconjugates play a pivotal role in many biological processes. In the airways, sialylated glycoproteins and glycolipids are strategically positioned on the plasma membranes of epithelia to regulate receptor-ligand, cell-cell, and host-pathogen interactions at the molecular level. We now demonstrate, for the first time, sialidase activity for ganglioside substrates in human airway epithelia. Of the four known mammalian sialidases, NEU3 has a substrate preference for gangliosides and is expressed at mRNA and protein levels at comparable abundance in epithelia derived from human trachea, bronchi, small airways, and alveoli. In small airway and alveolar epithelia, NEU3 protein was immunolocalized to the plasma membrane, cytosolic, and nuclear subcellular fractions. Small interfering RNA-induced silencing of NEU3 expression diminished sialidase activity for a ganglioside substrate by >70%. NEU3 immunostaining of intact human lung tissue could be localized to the superficial epithelia, including the ciliated brush border, as well as to nuclei. However, NEU3 was reduced in subepithelial tissues. These results indicate that human airway epithelia express catalytically active NEU3 sialidase. PMID:24658138

  12. Effect of airway inflammation on smooth muscle shortening and contractility in guinea pig trachealis.

    PubMed

    Mitchell, R W; Ndukwu, I M; Arbetter, K; Solway, J; Leff, A R

    1993-12-01

    We studied the effect of either 1) immunogenic inflammation caused by aerosolized ovalbumin or 2) neurogenic inflammation caused by aerosolized capsaicin in vivo on guinea pig tracheal smooth muscle (TSM) contractility in vitro. Force-velocity relationships were determined for nine epithelium-intact TSM strips from ovalbumin-sensitized (OAS) vs. seven sham-sensitized controls and TSM strips for seven animals treated with capsaicin aerosol (Cap-Aer) vs. eight sham controls. Muscle strips were tethered to an electromagnetic lever system, which allowed isotonic shortening when load clamps [from 0 to maximal isometric force (Po)] were applied at specific times after onset of contraction. Contractions were elicited by supramaximal electrical field stimulation (60 Hz, 10-s duration, 18 V). Optimal length for each muscle was determined during equilibration. Maximal shortening velocity (Vmax) was increased in TSM from OAS (1.72 +/- 0.46 mm/s) compared with sham-sensitized animals (0.90 +/- 0.15 mm/s, P < 0.05); Vmax for TSM from Cap-Aer (0.88 +/- 0.11 mm/s) was not different from control TSM (1.13 +/- 0.08 mm/s, P = NS). Similarly, maximal shortening (delta max) was augmented in TSM from OAS (1.01 +/- 0.15 mm) compared with sham-sensitized animals (0.72 +/- 0.14 mm, P < 0.05); delta max for TSM from Cap-Aer animals (0.65 +/- 0.11 mm) was not different from saline aerosol controls (0.71 +/- 0.15 mm, P = NS). We demonstrate Vmax and delta max are augmented in TSM after ovalbumin sensitization; in contrast, neurogenic inflammation caused by capsaicin has no effect on isolated TSM contractility in vitro. These data suggest that airway hyperresponsiveness in vivo that occurs in association with immunogenic or neurogenic inflammation may result from different effects of these types of inflammation on airway smooth muscle. PMID:8279571

  13. Airway hyperresponsiveness in asthma: a problem of limited smooth muscle relaxation with inspiration.

    PubMed Central

    Skloot, G; Permutt, S; Togias, A

    1995-01-01

    We hypothesized that hyperresponsiveness in asthma is caused by an impairment in the ability of inspiration to stretch airway smooth muscle. If the hypothesis was correct, we reasoned that the sensitivity to inhaled methacholine in normal and asthmatic subjects should be the same if the challenge was carried out under conditions where deep inspirations were prohibited. 10 asthmatic and 10 normal subjects received increasing concentrations of inhaled methacholine under conditions where forced expirations from a normal end-tidal inspiration were performed. When no deep inspirations were allowed, the response to methacholine was similar in the normal and asthmatic subjects, compatible with the hypothesis we propose. Completely contrary to our expectations, however, was the marked responsivity to methacholine that remained in the normal subjects after deep breaths were initiated. 6 of the 10 normal subjects had > 20% reduction in forced expiratory volume in one second (FEV 1) at doses of methacholine < 8 mg/ml, whereas there was < 15% reduction with 75 mg/ml during routine challenge. The ability of normal subjects to develop asthmatic responses when the modulating effects of increases in lung volume was voluntarily suppressed suggests that an intrinsic impairment of the ability of inspiration to stretch airway smooth muscle is a major feature of asthma. PMID:7593627

  14. Laryngeal mask airway without muscle relaxant in femoral head replacement in elderly patients

    PubMed Central

    KONG, MING; LI, BEIPING; TIAN, YUNPING

    2016-01-01

    The number of elderly patients undergoing femoral head replacement surgeries is on the increase. These patients often suffer from comorbidity such as cardiovascular and cerebrovascular complications, which limits the ability of medical teams to employ anesthesia. Thus, alternative methods are required. The aim of this study was to examine the advantage of laryngeal mask airway (LMA) in the absence of muscle relaxant in elderly patients undergoing femoral head replacement operations. Fifty patients (27 males and 23 females) undergoing femoral head replacements were selected for the study between March 2013 and May 2014. The mean value for the age in this group was 74.6±12.5 years. The patients were randomly distributed into two groups of 25. One group was designated as the treatment group and the second group as the control group. For the treatment group, LMA without muscle relaxant was used, and the control group received routine anesthesia. Variations in heart rate (HR), mean arterial pressure (MAP) and oxygen saturation (SPO2) in the two groups were monitored at different times. Clinical efficacy and muscle relaxation effects were also analyzed. For the treatment group, the HR, MAP and SPO2 measurements did not reveal any significant variation while these values in the control group demonstrated important dissimilarities. Time to recovery, time to extubation and incidence of throat pain in the treatment group were all markedly decreased as compared to those in control group. The operation time in the treatment group was not significantly different to that of control group. The satisfaction of the muscle relaxation effect in the treatment group was significantly higher than that in the control group while the incidence of adverse reactions was not considerably different. In conclusion, the use of LMA without using muscle relaxant in femoral head replacement surgeries performed on elderly patients showed to be effective and safe. PMID:26889218

  15. Effects of cigarette smoke extract on human airway smooth muscle cells in COPD.

    PubMed

    Chen, Ling; Ge, Qi; Tjin, Gavin; Alkhouri, Hatem; Deng, Linghong; Brandsma, Corry-Anke; Adcock, Ian; Timens, Wim; Postma, Dirkje; Burgess, Janette K; Black, Judith L; Oliver, Brian G G

    2014-09-01

    We hypothesised that the response to cigarette smoke in airway smooth muscle (ASM) cells from smokers with chronic obstructive pulmonary disease (COPD) would be intrinsically different from smokers without COPD, producing greater pro-inflammatory mediators and factors relating to airway remodelling. ASM cells were obtained from smokers with or without COPD, and then stimulated with cigarette smoke extract (CSE) or transforming growth factor-β1. The production of chemokines and matrix metalloproteinases (MMPs) were measured by ELISA, and the deposition of collagens by extracellular matrix ELISA. The effects of CSE on cell attachment and wound healing were measured by toluidine blue attachment and cell tracker green wound healing assays. CSE increased the release of CXCL8 and CXCL1 from human ASM cells, and cells from smokers with COPD produced more CSE-induced CXCL1. The production of MMP-1, -3 and -10, and the deposition of collagen VIII alpha 1 (COL8A1) were increased by CSE, especially in the COPD group which had higher production of MMP-1 and deposition of COL8A1. CSE decreased ASM cell attachment and wound healing in the COPD group only. ASM cells from smokers with COPD were more sensitive to CSE stimulation, which may explain, in part, why some smokers develop COPD. PMID:24969654

  16. Baicalin inhibits PDGF-induced proliferation and migration of airway smooth muscle cells

    PubMed Central

    Yang, Guang; Li, Jian-Qiang; Bo, Jian-Ping; Wang, Bei; Tian, Xin-Rui; Liu, Tan-Zhen; Liu, Zhuo-La

    2015-01-01

    Airway smooth muscle (ASM) cell proliferation and migration play important roles in airway remodeling in asthma. In vitro platelet-derived growth factor (PDGF) induced ASM cell proliferation and migration. Baicalin is one of flavonoid extracts from Scutellaria baicalensis, which has an anti-asthma effect. However, little is known about its role in PDGF-induced proliferation and migration in rat ASM (RASM) cells. In this study, we aimed to investigate the effects of baicalin on PDGF-induced RASM cell proliferation and migration. We also identified the signaling pathway by which baicalin influences RASM cell proliferation and migration. In the current study, we demonstrated that baicalin suppressed PDGF-induced RASM cell proliferation, arrested PDGF-induced cell-cycle progression. It also suppressed PDGF-induced RASM cell migration. Furthermore, baicalin suppressed PDGF-induced expression of phosphorylated p38, ERK1/2 and JNK in RASM cells. In summary, our study is the first to show that baicalin pretreatment can significantly inhibit PDGF-induced RASM cell proliferation and migration by suppressing the MAPK signaling pathway, and baicalin may be a useful chemotherapeutic agent for asthma. PMID:26884970

  17. Effects of Active Individual Muscle Stretching on Muscle Function

    PubMed Central

    Nakamura, Kouichi; Kodama, Takayuki; Mukaino, Yoshito

    2014-01-01

    [Purpose] We investigated the effect of active individual muscle stretching (AID) on muscle function. [Subjects] We used the right legs of 40 healthy male students. [Methods] Subjects were divided into an AID group, which performed stretching, and a control group, which did not. We examined and compared muscle function before and after stretching in the AID and control groups using a goniometer and Cybex equipment. [Results] A significant increase in flexibility and a significant decrease in muscle strength output were observed in the AID group after the intervention. [Conclusion] These results suggest that AID induces an increase in flexibility and a temporary decrease in muscle output strength. PMID:24707080

  18. Chronic effects of mechanical force on airways.

    PubMed

    Tschumperlin, Daniel J; Drazen, Jeffrey M

    2006-01-01

    Airways are embedded in the mechanically dynamic environment of the lung. In utero, this mechanical environment is defined largely by fluid secretion into the developing airway lumen. Clinical, whole lung, and cellular studies demonstrate pivotal roles for mechanical distention in airway morphogenesis and cellular behavior during lung development. In the adult lung, the mechanical environment is defined by a dynamic balance of surface, tissue, and muscle forces. Diseases of the airways modulate both the mechanical stresses to which the airways are exposed as well as the structure and mechanical behavior of the airways. For instance, in asthma, activation of airway smooth muscle abruptly changes the airway size and stress state within the airway wall; asthma also results in profound remodeling of the airway wall. Data now demonstrate that airway epithelial cells, smooth muscle cells, and fibroblasts respond to their mechanical environment. A prominent role has been identified for the epithelium in transducing mechanical stresses, and in both the fetal and mature airways, epithelial cells interact with mesenchymal cells to coordinate remodeling of tissue architecture in response to the mechanical environment. PMID:16460284

  19. Role of Dystrophin in Airway Smooth Muscle Phenotype, Contraction and Lung Function

    PubMed Central

    Sharma, Pawan; Basu, Sujata; Mitchell, Richard W.; Stelmack, Gerald L.; Anderson, Judy E.; Halayko, Andrew J.

    2014-01-01

    Dystrophin links the transmembrane dystrophin-glycoprotein complex to the actin cytoskeleton. We have shown that dystrophin-glycoprotein complex subunits are markers for airway smooth muscle phenotype maturation and together with caveolin-1, play an important role in calcium homeostasis. We tested if dystrophin affects phenotype maturation, tracheal contraction and lung physiology. We used dystrophin deficient Golden Retriever dogs (GRMD) and mdx mice vs healthy control animals in our approach. We found significant reduction of contractile protein markers: smooth muscle myosin heavy chain (smMHC) and calponin and reduced Ca2+ response to contractile agonist in dystrophin deficient cells. Immunocytochemistry revealed reduced stress fibers and number of smMHC positive cells in dystrophin-deficient cells, when compared to control. Immunoblot analysis of Akt1, GSK3β and mTOR phosphorylation further revealed that downstream PI3K signaling, which is essential for phenotype maturation, was suppressed in dystrophin deficient cell cultures. Tracheal rings from mdx mice showed significant reduction in the isometric contraction to methacholine (MCh) when compared to genetic control BL10ScSnJ mice (wild-type). In vivo lung function studies using a small animal ventilator revealed a significant reduction in peak airway resistance induced by maximum concentrations of inhaled MCh in mdx mice, while there was no change in other lung function parameters. These data show that the lack of dystrophin is associated with a concomitant suppression of ASM cell phenotype maturation in vitro, ASM contraction ex vivo and lung function in vivo, indicating that a linkage between the DGC and the actin cytoskeleton via dystrophin is a determinant of the phenotype and functional properties of ASM. PMID:25054970

  20. Biomechanical effects of environmental and engineered particles on human airway smooth muscle cells

    PubMed Central

    Berntsen, P.; Park, C. Y.; Rothen-Rutishauser, B.; Tsuda, A.; Sager, T. M.; Molina, R. M.; Donaghey, T. C.; Alencar, A. M.; Kasahara, D. I.; Ericsson, T.; Millet, E. J.; Swenson, J.; Tschumperlin, D. J.; Butler, J. P.; Brain, J. D.; Fredberg, J. J.; Gehr, P.; Zhou, E. H.

    2010-01-01

    The past decade has seen significant increases in combustion-generated ambient particles, which contain a nanosized fraction (less than 100 nm), and even greater increases have occurred in engineered nanoparticles (NPs) propelled by the booming nanotechnology industry. Although inhalation of these particulates has become a public health concern, human health effects and mechanisms of action for NPs are not well understood. Focusing on the human airway smooth muscle cell, here we show that the cellular mechanical function is altered by particulate exposure in a manner that is dependent upon particle material, size and dose. We used Alamar Blue assay to measure cell viability and optical magnetic twisting cytometry to measure cell stiffness and agonist-induced contractility. The eight particle species fell into four categories, based on their respective effect on cell viability and on mechanical function. Cell viability was impaired and cell contractility was decreased by (i) zinc oxide (40–100 nm and less than 44 μm) and copper(II) oxide (less than 50 nm); cell contractility was decreased by (ii) fluorescent polystyrene spheres (40 nm), increased by (iii) welding fumes and unchanged by (iv) diesel exhaust particles, titanium dioxide (25 nm) and copper(II) oxide (less than 5 μm), although in none of these cases was cell viability impaired. Treatment with hydrogen peroxide up to 500 μM did not alter viability or cell mechanics, suggesting that the particle effects are unlikely to be mediated by particle-generated reactive oxygen species. Our results highlight the susceptibility of cellular mechanical function to particulate exposures and suggest that direct exposure of the airway smooth muscle cells to particulates may initiate or aggravate respiratory diseases. PMID:20356875

  1. Effect of different bronchodilators on airway smooth muscle responsiveness to contractile agents.

    PubMed

    Gustafsson, B; Persson, C G

    1991-05-01

    "Functional antagonism" is often used to describe the general relaxant effect of beta 2 agonists and xanthines and their ability to protect the airways against bronchoconstrictor stimuli. This study in guinea pig isolated trachea addresses the question of whether the capacity of these drugs to protect against constrictor stimuli is related to smooth muscle relaxation. Three antimuscarinic drugs were also examined to determine whether antagonism of mediators other than muscarinic agonists might contribute to bronchodilatation by these antimuscarinic drugs. Terbutaline (1.1 x 10(-7), 2.2 x 10(-7) M), theophylline (2.2 x 10(-4), 4.4 x 10(-4) M), and enprofylline (5.2 x 10(-5), 1.0 x 10(-4) M) relaxed the tracheal tension that remained after indomethacin treatment. They did not, however, alter the carbachol concentration-response curve significantly. In addition, neither theophylline (2.2 x 10(-4) M) nor terbutaline (1.1 x 10(-7) M) altered histamine induced contraction. Atropine sulphate, glycopyrrolate, and ipratropium bromide had EC50 values of 10(-9) - 10(-8) M for relaxation of carbachol induced contractions, whereas concentrations of 10(-6) - 10(-3) M or greater were required to relax contractions induced by allergen and nine other non-muscarinic mediators. It is suggested that bronchodilatation by antimuscarinic drugs in vivo is due to inhibition of acetylcholine induced bronchoconstriction alone and that beta 2 agonists and xanthines have poor ability to protect airway smooth muscle against constrictor stimuli. Hence mechanisms other than bronchodilatation and "functional antagonism" should be considered to explain the protection against constrictor stimuli in asthma seen with beta 2 agonists and xanthines. PMID:2068693

  2. Biomechanical effects of environmental and engineered particles on human airway smooth muscle cells.

    PubMed

    Berntsen, P; Park, C Y; Rothen-Rutishauser, B; Tsuda, A; Sager, T M; Molina, R M; Donaghey, T C; Alencar, A M; Kasahara, D I; Ericsson, T; Millet, E J; Swenson, J; Tschumperlin, D J; Butler, J P; Brain, J D; Fredberg, J J; Gehr, P; Zhou, E H

    2010-06-01

    The past decade has seen significant increases in combustion-generated ambient particles, which contain a nanosized fraction (less than 100 nm), and even greater increases have occurred in engineered nanoparticles (NPs) propelled by the booming nanotechnology industry. Although inhalation of these particulates has become a public health concern, human health effects and mechanisms of action for NPs are not well understood. Focusing on the human airway smooth muscle cell, here we show that the cellular mechanical function is altered by particulate exposure in a manner that is dependent upon particle material, size and dose. We used Alamar Blue assay to measure cell viability and optical magnetic twisting cytometry to measure cell stiffness and agonist-induced contractility. The eight particle species fell into four categories, based on their respective effect on cell viability and on mechanical function. Cell viability was impaired and cell contractility was decreased by (i) zinc oxide (40-100 nm and less than 44 microm) and copper(II) oxide (less than 50 nm); cell contractility was decreased by (ii) fluorescent polystyrene spheres (40 nm), increased by (iii) welding fumes and unchanged by (iv) diesel exhaust particles, titanium dioxide (25 nm) and copper(II) oxide (less than 5 microm), although in none of these cases was cell viability impaired. Treatment with hydrogen peroxide up to 500 microM did not alter viability or cell mechanics, suggesting that the particle effects are unlikely to be mediated by particle-generated reactive oxygen species. Our results highlight the susceptibility of cellular mechanical function to particulate exposures and suggest that direct exposure of the airway smooth muscle cells to particulates may initiate or aggravate respiratory diseases. PMID:20356875

  3. Human airway smooth muscle maintain in situ cell orientation and phenotype when cultured on aligned electrospun scaffolds

    PubMed Central

    Morris, G. E.; Bridge, J. C.; Eltboli, O. M. I.; Lewis, M. P.; Knox, A. J.; Aylott, J. W.; Brightling, C. E.; Ghaemmaghami, A. M.

    2014-01-01

    Human airway smooth muscle (HASM) contraction plays a central role in regulating airway resistance in both healthy and asthmatic bronchioles. In vitro studies that investigate the intricate mechanisms that regulate this contractile process are predominantly conducted on tissue culture plastic, a rigid, 2D geometry, unlike the 3D microenvironment smooth muscle cells are exposed to in situ. It is increasingly apparent that cellular characteristics and responses are altered between cells cultured on 2D substrates compared with 3D topographies. Electrospinning is an attractive method to produce 3D topographies for cell culturing as the fibers produced have dimensions within the nanometer range, similar to cells' natural environment. We have developed an electrospun scaffold using the nondegradable, nontoxic, polymer polyethylene terephthalate (PET) composed of uniaxially orientated nanofibers and have evaluated this topography's effect on HASM cell adhesion, alignment, and morphology. The fibers orientation provided contact guidance enabling the formation of fully aligned sheets of smooth muscle. Moreover, smooth muscle cells cultured on the scaffold present an elongated cell phenotype with altered contractile protein levels and distribution. HASM cells cultured on this scaffold responded to the bronchoconstrictor bradykinin. The platform presented provides a novel in vitro model that promotes airway smooth muscle cell development toward a more in vivo-like phenotype while providing topological cues to ensure full cell alignment. PMID:24793171

  4. Effects of genetic obesity on rat upper airway muscle and diaphragm contractile properties.

    PubMed

    van Lunteren, E

    1996-10-01

    The contractile properties of pharyngeal respiratory muscle are altered in sleep apnoea and in conditions associated with sleep apnoea, such as ageing. We hypothesized that the contractile properties of the pharyngeal musculature are also altered by obesity, another factor associated with sleep apnoea. Studies compared a pharyngeal muscle, the sternohyoid, with the diaphragm. These were chosen as representative muscles whose contraction has opposing effects on upper airway patency. Both muscles were removed from nine lean and nine obese male Zucker rats (a genetic model of obesity), and isometric contractile properties were studied in vitro at 37 degrees C. For the sternohyoid muscle, in obese compared to lean animals there were no significant differences in isometric contraction time (15.2 +/- 0.3 vs 14.2 +/- 0.6 ms, respectively), half-relaxation time (13.6 +/- 0.5 vs 12.6 +/- 0.9 ms, respectively), twitch-to-tetanic tension ratio (0.22 +/- 0.02 vs 0.24 +/- 0.02, respectively), force-frequency relationship, fatigue resistance (2 min fatigue index 0.20 +/- 0.03 vs 0.18 +/- 0.02, respectively), or maximal degree of force potentiation during repetitive stimulation (52 +/- 11 vs 74 +/- 20% increase, respectively). For the diaphragm, the only significant effect of obesity was a lowering of the twitch-to-tetanic tension ratio (0.25 +/- 0.01 vs 0.29 +/- 0.02, respectively). In obese, as in lean animals, the sternohyoid had faster isometric twitch kinetics, a larger degree of force potentiation, and lower resistance to fatigue, than the diaphragm. In lean, but not obese, animals the sternohyoid twitch-to-tetanic tension ratio was lower than and the force frequency relationship was located to the right of that of the diaphragm. In this study, genetic obesity in rats was not associated with any significant alterations in the contractile properties of the pharyngeal muscle, and only small changes in the relationship between the contractile properties of the sternohyoid and

  5. Upper Airway Genioglossal Activity in Children with Sickle Cell Disease

    PubMed Central

    Huang, Jingtao; Pinto, Swaroop J.; Allen, Julian L.; Arens, Raanan; Bowdre, Cheryl Y.; Jawad, Abbas F.; Mason, Thornton B.A.; Ohene-Frempong, Kwaku; Smith-Whitley, Kim; Marcus, Carole L.

    2011-01-01

    Study Objectives: The prevalence of obstructive sleep apnea syndrome (OSAS) in sickle cell disease (SCD) has been reported to be higher than that in the general pediatric population. However, not all subjects with SCD develop OSAS. We hypothesized that SCD patients with OSAS have a blunted neuromuscular response to subatmospheric pressure loads during sleep, making them more likely to develop upper airway collapse. Design: Subjects with SCD with and without OSAS underwent pressure-flow measurements during sleep using intraoral surface electrodes to measure genioglossal EMG (EMGgg). Two techniques were applied to decrease the nasal pressure (PN) to subatmospheric levels, resulting in an activated and relatively hypotonic upper airway. The area under the curve of the inspiratory EMGgg moving time average was analyzed. EMGgg activity was expressed as a percentage of baseline. Changes in EMGgg in response to decrements in nasal pressure were expressed as the slope of the EMGgg vs. nasal pressure (slope of EMGgg-PN). Setting: Sleep laboratory. Participants: 4 children with SCD and OSAS and 18 children with SCD but without OSAS. Results: The major findings of this study were: (1) using the activated but not the hypotonic technique, the slope of EMGgg-PN was more negative in SCD controls than SCD OSAS; (2) the slope of EMGgg-PN was significantly lower using the activated technique compared to the hypotonic technique in SCD controls only; (3) similarly, the critical closing pressure, Pcrit, was more negative using the activated technique than the hypotonic technique in SCD controls but not in SCD OSAS. Conclusion: This preliminary study has shown that children with SCD but without OSAS have more prominent upper airway reflexes than children with SCD and OSAS. Citation: Huang J; Pinto SJ; Allen JL; Arens R; Bowdre CY; Jawad AF; Mason TBA; Ohene-Frempong K; Smith-Whitely K; Marcus CL. Upper airway genioglossal activity in children with sickle cell disease. SLEEP 2011

  6. Vitamin D deficiency causes airway hyperresponsiveness, increases airway smooth muscle mass, and reduces TGF‐β expression in the lungs of female BALB/c mice

    PubMed Central

    Foong, Rachel E.; Shaw, Nicole C.; Berry, Luke J.; Hart, Prue H.; Gorman, Shelley; Zosky, Graeme R.

    2014-01-01

    Abstract Vitamin D deficiency is associated with disease severity in asthma. We tested whether there is a causal association between vitamin D deficiency, airway smooth muscle (ASM) mass, and the development of airway hyperresponsiveness (AHR). A physiologically relevant mouse model of vitamin D deficiency was developed by raising BALB/c mice on vitamin D‐deficient or ‐replete diets. AHR was assessed by measuring lung function responses to increasing doses of inhaled methacholine. Five‐micron sections from formalin‐fixed lungs were used for ASM measurement and assessment of lung structure using stereological methods. Transforming growth factor (TGF)‐β levels were measured in bronchoalveolar lavage fluid (BALF). Lungs were dissected from embryonic day (E) 17.5 vitamin D‐deficient and ‐replete fetal mice for quantification of ASM density and relative gene expression of TGF‐β signaling pathway molecules. Eight‐week‐old adult vitamin D‐deficient female mice had significantly increased airway resistance and ASM in the large airways compared with controls. Vitamin D‐deficient female mice had a smaller lung volume, volume of parenchyma, and alveolar septa. Both vitamin D‐deficient male and female mice had reduced TGF‐β levels in BALF. Vitamin D deficiency did not have an effect on ASM density in E17.5 mice, however, expression of TGF‐β1 and TGF‐β receptor I was downregulated in vitamin D‐deficient female fetal mice. Decreased expression of TGF‐β1 and TGF‐β receptor I during early lung development in vitamin D‐deficient mice may contribute to airway remodeling and AHR in vitamin D‐deficient adult female mice. This study provides a link between vitamin D deficiency and respiratory symptoms in chronic lung disease. PMID:24760528

  7. Nanotubes connect CD4+ T cells to airway smooth muscle cells: novel mechanism of T cell survival.

    PubMed

    Al Heialy, Saba; Zeroual, Melissa; Farahnak, Soroor; McGovern, Toby; Risse, Paul-André; Novali, Mauro; Lauzon, Anne-Marie; Roman, Horia N; Martin, James G

    2015-06-15

    Contact between airway smooth muscle (ASM) cells and activated CD4(+) T cells, a key interaction in diseases such as asthma, triggers ASM cell proliferation and enhances T cell survival. We hypothesized that direct contact between ASM and CD4(+) T cells facilitated the transfer of anti-apoptotic proteins via nanotubes, resulting in increased survival of activated CD4(+) T cells. CD4(+) T cells, isolated from PBMCs of healthy subjects, when activated and cocultured with ASM cells for 24 h, formed nanotubes that were visualized by immunofluorescence and atomic force microscopy. Cell-to-cell transfer of the fluorescent dye calcein-AM confirmed cytoplasmic communication via nanotubes. Immunoreactive B cell lymphoma 2 (Bcl-2) and induced myeloid leukemia cell differentiation protein (Mcl-1), two major anti-apoptotic proteins, were present within the nanotubes. Downregulation of Mcl-1 by small interfering RNA in ASM cells significantly increased T cell apoptosis, whereas downregulation of Bcl-2 had no effect. Transfer of GFP-tagged Mcl-1 from ASM cells to CD4(+) T cells via the nanotubes confirmed directionality of transfer. In conclusion, activated T cells communicate with ASM cells via nanotube formation. Direct transfer of Mcl-1 from ASM to CD(+) T cells via nanotubes is involved in T cell survival. This study provides a novel mechanism of survival of CD4(+) T cells that is dependent on interaction with a structural cell. PMID:25934863

  8. Airway occlusion pressure and diaphragm global electromyogram analysis for evaluation of inspiratory muscle drive and neuromechanical coupling in cattle.

    PubMed

    Desmecht, D J; Linden, A S; Rollin, F A; Lekeux, P M

    1994-06-01

    Although healthy and diseased bovine respiratory tracts have been intensively studied during the last years, to the authors' knowledge, there have been no attempts to objectively examine the inspiratory drive from the brain to the nerves and muscles and its transformation in pressure. Such technique would be useful in assessing the possibility of altered ventilatory drive or inspiratory muscle fatigue in the context of an animal with ventilatory failure. The relation among ventilation, airway opening occlusion pressure generated 100 milliseconds after onset of inspiration (Pawo100ms) and 6 indexes describing diaphragmatic electromyographic activity (EMGdi) recorded via implanted fishhooks was evaluated during free and impeded CO2 rebreathing in 6 young bulls. The best significant linear correlations (r > 0.8) with inspiratory center afferent stimulation, as judged by end-tidal CO2 concentration in expired air, were found for Pawo100ms, peak moving time average or variance EMGdi, and mean integrated EMGdi, whatever had been the respiratory impedance. However, with an inspiratory load, Pawo100ms responses systematically had greater increase for a given change in the driving EMGdi, implying dependence of the former not only on neural input, but also on configurational factors that determine inspiratory muscle excitation-pressure generation couplings. The reproducibility of EMGdi absolute values and changes was satisfactory up to 10 hours, but could not be repeated from one day to the other. It was concluded that, provided the constancy of the electrical coupling of the recording system to the tissue being studied is ensured, specific EMGdi and Pawo100ms values correlate reliably with amount of CO2 during free and loaded breathing.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7944009

  9. Development and characterization of a 3D multicell microtissue culture model of airway smooth muscle

    PubMed Central

    Zaman, Nishat; Cole, Darren J.; Walker, Matthew J.; Legant, Wesley R.; Boudou, Thomas; Chen, Christopher S.; Favreau, John T.; Gaudette, Glenn R.; Cowley, Elizabeth A.; Maksym, Geoffrey N.

    2013-01-01

    Airway smooth muscle (ASM) cellular and molecular biology is typically studied with single-cell cultures grown on flat 2D substrates. However, cells in vivo exist as part of complex 3D structures, and it is well established in other cell types that altering substrate geometry exerts potent effects on phenotype and function. These factors may be especially relevant to asthma, a disease characterized by structural remodeling of the airway wall, and highlights a need for more physiologically relevant models of ASM function. We utilized a tissue engineering platform known as microfabricated tissue gauges to develop a 3D culture model of ASM featuring arrays of ∼0.4 mm long, ∼350 cell “microtissues” capable of simultaneous contractile force measurement and cell-level microscopy. ASM-only microtissues generated baseline tension, exhibited strong cellular organization, and developed actin stress fibers, but lost structural integrity and dissociated from the cantilevers within 3 days. Addition of 3T3-fibroblasts dramatically improved survival times without affecting tension development or morphology. ASM-3T3 microtissues contracted similarly to ex vivo ASM, exhibiting reproducible responses to a range of contractile and relaxant agents. Compared with 2D cultures, microtissues demonstrated identical responses to acetylcholine and KCl, but not histamine, forskolin, or cytochalasin D, suggesting that contractility is regulated by substrate geometry. Microtissues represent a novel model for studying ASM, incorporating a physiological 3D structure, realistic mechanical environment, coculture of multiple cells types, and comparable contractile properties to existing models. This new model allows for rapid screening of biochemical and mechanical factors to provide insight into ASM dysfunction in asthma. PMID:23125251

  10. MicroRNA Mediated Chemokine Responses in Human Airway Smooth Muscle Cells

    PubMed Central

    Dileepan, Mythili; Sarver, Anne E.; Rao, Savita P.; Panettieri, Reynold A.; Subramanian, Subbaya; Kannan, Mathur S.

    2016-01-01

    Airway smooth muscle (ASM) cells play a critical role in the pathophysiology of asthma due to their hypercontractility and their ability to proliferate and secrete inflammatory mediators. microRNAs (miRNAs) are gene regulators that control many signaling pathways and thus serve as potential therapeutic alternatives for many diseases. We have previously shown that miR-708 and miR-140-3p regulate the MAPK and PI3K signaling pathways in human ASM (HASM) cells following TNF-α exposure. In this study, we investigated the regulatory effect of these miRNAs on other asthma-related genes. Microarray analysis using the Illumina platform was performed with total RNA extracted from miR-708 (or control miR)-transfected HASM cells. Inhibition of candidate inflammation-associated gene expression was further validated by qPCR and ELISA. The most significant biologic functions for the differentially expressed gene set included decreased inflammatory response, cytokine expression and signaling. qPCR revealed inhibition of expression of CCL11, CXCL10, CCL2 and CXCL8, while the release of CCL11 was inhibited in miR-708-transfected cells. Transfection of cells with miR-140-3p resulted in inhibition of expression of CCL11, CXCL12, CXCL10, CCL5 and CXCL8 and of TNF-α-induced CXCL12 release. In addition, expression of RARRES2, CD44 and ADAM33, genes known to contribute to the pathophysiology of asthma, were found to be inhibited in miR-708-transfected cells. These results demonstrate that miR-708 and miR-140-3p exert distinct effects on inflammation-associated gene expression and biological function of ASM cells. Targeting these miRNA networks may provide a novel therapeutic mechanism to down-regulate airway inflammation and ASM proliferation in asthma. PMID:26998837

  11. Airway smooth muscle inflammation is regulated by microRNA-145 in COPD.

    PubMed

    O'Leary, Lawrence; Sevinç, Kenan; Papazoglou, Ilektra M; Tildy, Bernadett; Detillieux, Karen; Halayko, Andrew J; Chung, Kian Fan; Perry, Mark M

    2016-05-01

    Chronic obstructive pulmonary disease (COPD) is a common, highly debilitating disease of the airways, primarily caused by smoking. Chronic inflammation and structural remodelling are key pathological features of this disease, in part caused by the aberrant function of airway smooth muscle (ASM) cells under the regulation of transforming growth factor (TGF)-β. miRNA are short, noncoding gene transcripts involved in the negative regulation of specific target genes, through their interactions with mRNA. Previous studies have proposed that mRNA-145 (miR-145) may interact with SMAD3, an important downstream signalling molecule of the TGF-β pathway. TGF-β was used to stimulate primary human ASM cells isolated from healthy nonsmokers, healthy smokers and COPD patients. This resulted in a TGF-β-dependent increase in CXCL8 and IL-6 release, most notably in the cells from COPD patients. TGF-β stimulation increased SMAD3 expression, only in cells from COPD patients, with a concurrent increased miR-145 expression. Regulation of miR-145 was found to be negatively controlled by pathways involving the MAP kinases, MEK-1/2 and p38 MAPK. Subsequent, overexpression of miR-145 (using synthetic mimics) in ASM cells from patients with COPD suppressed IL-6 and CXCL8 release, to levels comparable to the nonsmoker controls. Therefore, this study suggests that miR-145 negatively regulates pro-inflammatory cytokine release from ASM cells in COPD by targeting SMAD3. PMID:27060571

  12. MicroRNA Mediated Chemokine Responses in Human Airway Smooth Muscle Cells.

    PubMed

    Dileepan, Mythili; Sarver, Anne E; Rao, Savita P; Panettieri, Reynold A; Subramanian, Subbaya; Kannan, Mathur S

    2016-01-01

    Airway smooth muscle (ASM) cells play a critical role in the pathophysiology of asthma due to their hypercontractility and their ability to proliferate and secrete inflammatory mediators. microRNAs (miRNAs) are gene regulators that control many signaling pathways and thus serve as potential therapeutic alternatives for many diseases. We have previously shown that miR-708 and miR-140-3p regulate the MAPK and PI3K signaling pathways in human ASM (HASM) cells following TNF-α exposure. In this study, we investigated the regulatory effect of these miRNAs on other asthma-related genes. Microarray analysis using the Illumina platform was performed with total RNA extracted from miR-708 (or control miR)-transfected HASM cells. Inhibition of candidate inflammation-associated gene expression was further validated by qPCR and ELISA. The most significant biologic functions for the differentially expressed gene set included decreased inflammatory response, cytokine expression and signaling. qPCR revealed inhibition of expression of CCL11, CXCL10, CCL2 and CXCL8, while the release of CCL11 was inhibited in miR-708-transfected cells. Transfection of cells with miR-140-3p resulted in inhibition of expression of CCL11, CXCL12, CXCL10, CCL5 and CXCL8 and of TNF-α-induced CXCL12 release. In addition, expression of RARRES2, CD44 and ADAM33, genes known to contribute to the pathophysiology of asthma, were found to be inhibited in miR-708-transfected cells. These results demonstrate that miR-708 and miR-140-3p exert distinct effects on inflammation-associated gene expression and biological function of ASM cells. Targeting these miRNA networks may provide a novel therapeutic mechanism to down-regulate airway inflammation and ASM proliferation in asthma. PMID:26998837

  13. Complement activation promotes muscle inflammation during modified muscle use

    NASA Technical Reports Server (NTRS)

    Frenette, J.; Cai, B.; Tidball, J. G.

    2000-01-01

    Modified muscle use can result in muscle inflammation that is triggered by unidentified events. In the present investigation, we tested whether the activation of the complement system is a component of muscle inflammation that results from changes in muscle loading. Modified rat hindlimb muscle loading was achieved by removing weight-bearing from the hindlimbs for 10 days followed by reloading through normal ambulation. Experimental animals were injected with the recombinant, soluble complement receptor sCR1 to inhibit complement activation. Assays for complement C4 or factor B in sera showed that sCR1 produced large reductions in the capacity for activation of the complement system through both the classical and alternative pathways. Analysis of complement C4 concentration in serum in untreated animals showed that the classical pathway was activated during the first 2 hours of reloading. Analysis of factor B concentration in untreated animals showed activation of the alternative pathway at 6 hours of reloading. Administration of sCR1 significantly attenuated the invasion of neutrophils (-49%) and ED1(+) macrophages (-52%) that occurred in nontreated animals after 6 hours of reloading. The presence of sCR1 also reduced significantly the degree of edema by 22% as compared to untreated animals. Together, these data show that increased muscle loading activated the complement system which then briefly contributes to the early recruitment of inflammatory cells during modified muscle loading.

  14. Assays for in vitro monitoring of proliferation of human airway smooth muscle (ASM) and human pulmonary arterial vascular smooth muscle (VSM) cells.

    PubMed

    Goncharova, Elena A; Lim, Poay; Goncharov, Dmitry A; Eszterhas, Andrew; Panettieri, Reynold A; Krymskaya, Vera P

    2006-01-01

    Vascular and airway remodeling, which are characterized by airway smooth muscle (ASM) and pulmonary arterial vascular smooth muscle (VSM) proliferation, contribute to the pathology of asthma, pulmonary hypertension, restenosis and atherosclerosis. To evaluate the proliferation of VSM and ASM cells in response to mitogens, we perform a [3H]thymidine incorporation assay. The proliferation protocol takes approximately 48 h and includes stimulating cells synchronized in G0/G1 phase of the cell cycle with agonists, labeling cells with [3H]thymidine and examining levels of [3H]thymidine incorporation by scintillation counting. Although using radiolabeled [3H]thymidine incorporation is a limitation, the greatest benefit of the assay is providing reliable and statistically significant data. PMID:17406550

  15. Exploiting the relationship between birefringence and force to measure airway smooth muscle contraction with PS-OCT (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Adams, David C.; Hariri, Lida P.; Holz, Jasmin A.; Szabari, Margit V.; Harris, R. Scott; Cho, Jocelyn L.; Hamilos, Daniel L.; Luster, Andrew D.; Medoff, Benjamin D.; Suter, Melissa J.

    2016-03-01

    The ability to observe airway dynamics is fundamental to forming a complete understanding of pulmonary diseases such as asthma. We have previously demonstrated that Optical Coherence Tomography (OCT) can be used to observe structural changes in the airway during bronchoconstriction, but standard OCT lacks the contrast to discriminate airway smooth muscle (ASM) bands- ASM being responsible for generating the force that drives airway constriction- from the surrounding tissue. Since ASM in general exhibits a greater degree of birefringence than the surrounding tissue, a potential solution to this problem lies in the implementation of polarization sensitivity (PS) to the OCT system. By modifying the OCT system so that it is sensitive to the birefringence of tissue under inspection, we can visualize the ASM with much greater clarity and definition. In this presentation we show that the force of contraction can be indirectly measured by an associated increase in the birefringence signal of the ASM. We validate this approach by attaching segments of swine trachea to an isometric force transducer and stimulating contraction, while simultaneously measuring the exerted force and imaging the segment with PS-OCT. We then show how our results may be used to extrapolate the force of contraction of closed airways in absence of additional measurement devices. We apply this technique to assess ASM contractility volumetrically and in vivo, in both asthmatic and non-asthmatic human volunteers.

  16. Hydrogen sulphide inhibits Ca2+ release through InsP3 receptors and relaxes airway smooth muscle

    PubMed Central

    Castro-Piedras, Isabel; Perez-Zoghbi, Jose F

    2013-01-01

    Hydrogen sulphide (H2S) is a signalling molecule that appears to regulate diverse cell physiological process in several organs and systems including vascular and airway smooth muscle cell (SMC) contraction. Decreases in endogenous H2S synthesis have been associated with the development of cardiovascular diseases and asthma. Here we investigated the mechanism of airway SMC relaxation induced by H2S in small intrapulmonary airways using mouse lung slices and confocal and phase-contrast video microscopy. Exogenous H2S donor Na2S (100 μm) reversibly inhibited Ca2+ release and airway contraction evoked by inositol-1,4,5-trisphosphate (InsP3) uncaging in airway SMCs. Similarly, InsP3-evoked Ca2+ release and contraction was inhibited by endogenous H2S precursor l-cysteine (10 mm) but not by l-serine (10 mm) or either amino acid in the presence of dl-propargylglycine (PPG). Consistent with the inhibition of Ca2+ release through InsP3 receptors (InsP3Rs), Na2S reversibly inhibited acetylcholine (ACh)-induced Ca2+ oscillations in airway SMCs. In addition, Na2S, the H2S donor GYY-4137, and l-cysteine caused relaxation of airways pre-contracted with either ACh or 5-hydroxytryptamine (5-HT). Na2S-induced airway relaxation was resistant to a guanylyl cyclase inhibitor (ODQ) and a protein kinase G inhibitor (Rp-8-pCPT-cGMPS). The effects of H2S on InsP3-evoked Ca2+ release and contraction as well as on the relaxation of agonist-contracted airways were mimicked by the thiol-reducing agent dithiothreitol (DTT, 10 mm) and inhibited by the oxidizing agent diamide (30 μm). These studies indicate that H2S causes airway SMC relaxation by inhibiting Ca2+ release through InsP3Rs and consequent reduction of agonist-induced Ca2+ oscillations in SMCs. The results suggest a novel role for endogenously produced H2S that involves the modulation of InsP3-evoked Ca2+ release – a cell-signalling system of critical importance for many physiological and pathophysiological processes. PMID

  17. Hydrogen sulphide inhibits Ca2+ release through InsP3 receptors and relaxes airway smooth muscle.

    PubMed

    Castro-Piedras, Isabel; Perez-Zoghbi, Jose F

    2013-12-01

    Hydrogen sulphide (H2S) is a signalling molecule that appears to regulate diverse cell physiological process in several organs and systems including vascular and airway smooth muscle cell (SMC) contraction. Decreases in endogenous H2S synthesis have been associated with the development of cardiovascular diseases and asthma. Here we investigated the mechanism of airway SMC relaxation induced by H2S in small intrapulmonary airways using mouse lung slices and confocal and phase-contrast video microscopy. Exogenous H2S donor Na2S (100 μm) reversibly inhibited Ca(2+) release and airway contraction evoked by inositol-1,4,5-trisphosphate (InsP3) uncaging in airway SMCs. Similarly, InsP3-evoked Ca(2+) release and contraction was inhibited by endogenous H2S precursor l-cysteine (10 mm) but not by l-serine (10 mm) or either amino acid in the presence of dl-propargylglycine (PPG). Consistent with the inhibition of Ca(2+) release through InsP3 receptors (InsP3Rs), Na2S reversibly inhibited acetylcholine (ACh)-induced Ca(2+) oscillations in airway SMCs. In addition, Na2S, the H2S donor GYY-4137, and l-cysteine caused relaxation of airways pre-contracted with either ACh or 5-hydroxytryptamine (5-HT). Na2S-induced airway relaxation was resistant to a guanylyl cyclase inhibitor (ODQ) and a protein kinase G inhibitor (Rp-8-pCPT-cGMPS). The effects of H2S on InsP3-evoked Ca(2+) release and contraction as well as on the relaxation of agonist-contracted airways were mimicked by the thiol-reducing agent dithiothreitol (DTT, 10 mm) and inhibited by the oxidizing agent diamide (30 μm). These studies indicate that H2S causes airway SMC relaxation by inhibiting Ca(2+) release through InsP3Rs and consequent reduction of agonist-induced Ca(2+) oscillations in SMCs. The results suggest a novel role for endogenously produced H2S that involves the modulation of InsP3-evoked Ca(2+) release - a cell-signalling system of critical importance for many physiological and pathophysiological processes

  18. Motor unit regulation of mammalian pharyngeal dilator muscle activity.

    PubMed Central

    van Lunteren, E; Dick, T E

    1989-01-01

    The present study examined the cellular regulation of one of the pharyngeal dilator muscles, the geniohyoid, by assessing its motor unit (MU) behavior in anesthetized cats. During spontaneous breathing, MU that (a) were active during inspiration only (I-MU) and (b) were active during both inspiration and expiration (I/E-MU) were identified. I-MU had a later inspiratory onset time and a shorter duration of inspiratory firing than did I/E-MU (P less than 0.002 and P less than 0.0001, respectively). I-MU were usually quiescent whereas I/E-MU were usually active during the last 20% of inspiration. I/E-MU fired more rapidly (P less than 0.00001) and for relatively longer periods of time (P less than 0.00001) during inspiration than during expiration. End-expiratory airway occlusion (preventing lung expansion during inspiration) augmented the inspiratory activity of both I-MU and I/E-MU. Conversely, end-expiratory airway occlusion reduced the absolute and relative firing durations (P less than 0.002 and P less than 0.00002, respectively) and the firing frequency (P less than 0.001) of I/E-MU activity during expiration. These results indicate that (a) the complex pattern of pharyngeal dilator muscle activity is due to the integrated activity of a heterogeneous group of MU, (b) changes in the degree to which pharyngeal dilator muscles are active result from combinations of MU recruitment/decruitment and modulations of the frequency and duration of MU firing, and (c) gating of lung-volume afferent information occurs during the respiratory cycle. PMID:2760202

  19. Selective targeting of the α5-subunit of GABAA receptors relaxes airway smooth muscle and inhibits cellular calcium handling

    PubMed Central

    Yocum, Gene T.; Siviski, Matthew E.; Yim, Peter D.; Fu, Xiao Wen; Poe, Michael M.; Cook, James M.; Harrison, Neil; Perez-Zoghbi, Jose; Emala, Charles W.

    2015-01-01

    The clinical need for novel bronchodilators for the treatment of bronchoconstrictive diseases remains a major medical issue. Modulation of airway smooth muscle (ASM) chloride via GABAA receptor activation to achieve relaxation of precontracted ASM represents a potentially beneficial therapeutic option. Since human ASM GABAA receptors express only the α4- and α5-subunits, there is an opportunity to selectively target ASM GABAA receptors to improve drug efficacy and minimize side effects. Recently, a novel compound (R)-ethyl8-ethynyl-6-(2-fluorophenyl)-4-methyl-4H-benzo[f]imidazo[1,5-a][1,4] diazepine-3-carboxylate (SH-053-2′F-R-CH3) with allosteric selectivity for α5-subunit containing GABAA receptors has become available. We questioned whether this novel GABAA α5-selective ligand relaxes ASM and affects intracellular calcium concentration ([Ca2+]i) regulation. Immunohistochemical staining localized the GABAA α5-subunit to human ASM. The selective GABAA α5 ligand SH-053-2′F-R-CH3 relaxes precontracted intact ASM; increases GABA-activated chloride currents in human ASM cells in voltage-clamp electrophysiology studies; and attenuates bradykinin-induced increases in [Ca2+]i, store-operated Ca2+ entry, and methacholine-induced Ca2+ oscillations in peripheral murine lung slices. In conclusion, selective subunit targeting of endogenous α5-subunit containing GABAA receptors on ASM may represent a novel therapeutic option to treat severe bronchospasm. PMID:25659897

  20. Selective targeting of the α5-subunit of GABAA receptors relaxes airway smooth muscle and inhibits cellular calcium handling.

    PubMed

    Gallos, George; Yocum, Gene T; Siviski, Matthew E; Yim, Peter D; Fu, Xiao Wen; Poe, Michael M; Cook, James M; Harrison, Neil; Perez-Zoghbi, Jose; Emala, Charles W

    2015-05-01

    The clinical need for novel bronchodilators for the treatment of bronchoconstrictive diseases remains a major medical issue. Modulation of airway smooth muscle (ASM) chloride via GABAA receptor activation to achieve relaxation of precontracted ASM represents a potentially beneficial therapeutic option. Since human ASM GABAA receptors express only the α4- and α5-subunits, there is an opportunity to selectively target ASM GABAA receptors to improve drug efficacy and minimize side effects. Recently, a novel compound (R)-ethyl8-ethynyl-6-(2-fluorophenyl)-4-methyl-4H-benzo[f]imidazo[1,5-a][1,4] diazepine-3-carboxylate (SH-053-2'F-R-CH3) with allosteric selectivity for α5-subunit containing GABAA receptors has become available. We questioned whether this novel GABAA α5-selective ligand relaxes ASM and affects intracellular calcium concentration ([Ca(2+)]i) regulation. Immunohistochemical staining localized the GABAA α5-subunit to human ASM. The selective GABAA α5 ligand SH-053-2'F-R-CH3 relaxes precontracted intact ASM; increases GABA-activated chloride currents in human ASM cells in voltage-clamp electrophysiology studies; and attenuates bradykinin-induced increases in [Ca(2+)]i, store-operated Ca(2+) entry, and methacholine-induced Ca(2+) oscillations in peripheral murine lung slices. In conclusion, selective subunit targeting of endogenous α5-subunit containing GABAA receptors on ASM may represent a novel therapeutic option to treat severe bronchospasm. PMID:25659897

  1. Parabronchial smooth muscle constitutes an airway epithelial stem cell niche in the mouse lung after injury.

    PubMed

    Volckaert, Thomas; Dill, Erik; Campbell, Alice; Tiozzo, Caterina; Majka, Susan; Bellusci, Saverio; De Langhe, Stijn P

    2011-11-01

    During lung development, parabronchial SMC (PSMC) progenitors in the distal mesenchyme secrete fibroblast growth factor 10 (Fgf10), which acts on distal epithelial progenitors to promote their proliferation. β-catenin signaling within PSMC progenitors is essential for their maintenance, proliferation, and expression of Fgf10. Here, we report that this Wnt/Fgf10 embryonic signaling cascade is reactivated in mature PSMCs after naphthalene-induced injury to airway epithelium. Furthermore, we found that this paracrine Fgf10 action was essential for activating surviving variant Clara cells (the cells in the airway epithelium from which replacement epithelial cells originate) located at the bronchoalveolar duct junctions and adjacent to neuroendocrine bodies. After naphthalene injury, PSMCs secreted Fgf10 to activate Notch signaling and induce Snai1 expression in surviving variant Clara cells, which subsequently underwent a transient epithelial to mesenchymal transition to initiate the repair process. Epithelial Snai1 expression was important for regeneration after injury. We have therefore identified PSMCs as a stem cell niche for the variant Clara cells in the lung and established that paracrine Fgf10 signaling from the niche is critical for epithelial repair after naphthalene injury. These findings also have implications for understanding the misregulation of lung repair in asthma and cancer. PMID:21985786

  2. Influences of laryngeal afferent inputs on intralaryngeal muscle activity during vocalization in the cat.

    PubMed

    Shiba, K; Yoshida, K; Nakajima, Y; Konno, A

    1997-01-01

    The present study was undertaken to elucidate the possible role of the laryngeal afferent inputs in the regulation of intralaryngeal muscle activity during vocalization. We studied the influences of airflow and/or pressure applied to the larynx on intralaryngeal muscle activity during vocalization in ketamine-anesthetized cats. Vocalization was induced by airflow applied to the upper airway, which was isolated from the lower airway, during pontine call site stimulation. When the upper airway was open to the atmosphere through the nostrils and mouth, the airflow increased not only the vocal fold adductor and tensor activities but also the duration of these activities. The adductor and tensor activities were increased suddenly at a critical subglottic pressure level equivalent to the subglottic pressure threshold for vocalization. These effects were significantly reduced by sectioning of the internal branch of the superior laryngeal nerve or by lidocaine application to the laryngeal mucosa. Sustained pressure applied to the isolated upper airway, when the mouth and nostrils were occluded, did not affect adductor or tensor activities. These results indicate that the afferent inputs evoked by vocal fold stretching or vibration play an important role in the motor control of intralaryngeal and respiratory muscles during vocalization. PMID:9089702

  3. Tissue Inhibitor of Metalloproteinase-1 Moderates Airway Re-Epithelialization by Regulating Matrilysin Activity

    PubMed Central

    Chen, Peter; McGuire, John K.; Hackman, Robert C.; Kim, Kyoung-Hee; Black, Roy A.; Poindexter, Kurt; Yan, Wei; Liu, Phillip; Chen, Ann J.; Parks, William C.; Madtes, David K.

    2008-01-01

    Obliterative bronchiolitis (OB) is the histopathological finding in chronic lung allograft rejection. Mounting evidence suggests that epithelial damage drives the development of airway fibrosis in OB. Tissue inhibitor of metalloproteinase (TIMP)-1 expression increases in lung allografts and is associated with the onset of allograft rejection. Furthermore, in a mouse model of OB, airway obliteration is reduced in TIMP-1-deficient mice. Matrilysin (matrix metallproteinase-7) is essential for airway epithelial repair and is required for the re-epithelialization of airway wounds by facilitating cell migration; therefore, the goal of this study was to determine whether TIMP-1 inhibits re-epithelialization through matrilysin. We found that TIMP-1 and matrilysin co-localized in the epithelium of human lungs with OB and both co-localized and co-immunoprecipitated in wounded primary airway epithelial cultures. TIMP-1-deficient cultures migrated faster, and epithelial cells spread to a greater extent compared with wild-type cultures. TIMP-1 also inhibited matrilysin-mediated cell migration and spreading in vitro. In vivo, TIMP-1 deficiency enhanced airway re-epithelialization after naphthalene injury. Furthermore, TIMP-1 and matrilysin co-localized in airway epithelial cells adjacent to the wound edge. Our data demonstrate that TIMP-1 interacts with matrix metalloproteinases and regulates matrilysin activity during airway epithelial repair. Furthermore, we speculate that TIMP-1 overexpression restricts airway re-epithelialization by inhibiting matrilysin activity, contributing to a stereotypic injury response that promotes airway fibrosis via bronchiole airway epithelial damage and obliteration. PMID:18385523

  4. Glucocorticoid and TNF signaling converge at A20 (TNFAIP3) to repress airway smooth muscle cytokine expression.

    PubMed

    Sasse, Sarah K; Altonsy, Mohammed O; Kadiyala, Vineela; Cao, Gaoyuan; Panettieri, Reynold A; Gerber, Anthony N

    2016-08-01

    Airway smooth muscle is a major target tissue for glucocorticoid (GC)-based asthma therapies, however, molecular mechanisms through which the GC receptor (GR) exerts therapeutic effects in this key airway cell type have not been fully elucidated. We previously identified the nuclear factor-κB (NF-κB) inhibitor, A20 (TNFAIP3), as a mediator of cytokine repression by glucocorticoids (GCs) in airway epithelial cells and defined cooperative regulation of anti-inflammatory genes by GR and NF-κB as a key mechanistic underpinning of airway epithelial GR function. Here, we expand on these findings to determine whether a similar mechanism is operational in human airway smooth muscle (HASM). Using HASM cells derived from normal and fatal asthma samples as an in vitro model, we demonstrate that GCs spare or augment TNF-mediated induction of A20 (TNFAIP3), TNIP1, and NFKBIA, all implicated in negative feedback control of NF-κB-driven inflammatory processes. We applied chromatin immunoprecipitation and reporter analysis to show that GR and NF-κB directly regulate A20 expression in HASM through cooperative induction of an intronic enhancer. Using overexpression, we show for the first time that A20 and its interacting partner, TNIP1, repress TNF signaling in HASM cells. Moreover, we applied small interfering RNA-based gene knockdown to demonstrate that A20 is required for maximal cytokine repression by GCs in HASM. Taken together, our data suggest that inductive regulation of A20 by GR and NF-κB contributes to cytokine repression in HASM. PMID:27371733

  5. Strain-dependent activation of NF-kappaB in the airway epithelium and its role in allergic airway inflammation.

    PubMed

    Alcorn, John F; Ckless, Karina; Brown, Amy L; Guala, Amy S; Kolls, Jay K; Poynter, Matthew E; Irvin, Charles G; van der Vliet, Albert; Janssen-Heininger, Yvonne M W

    2010-01-01

    NF-kappaB activation in the airway epithelium has been established as a critical pathway in ovalbumin (Ova)-induced airway inflammation in BALB/c mice (Poynter ME, Cloots R, van Woerkom T, Butnor KJ, Vacek P, Taatjes DJ, Irvin CG, Janssen-Heininger YM. J Immunol 173: 7003-7009, 2004). BALB/c mice are susceptible to the development of allergic airway disease, whereas other strains of mice, such as C57BL/6, are considered more resistant. The goal of the present study was to determine the proximal signals required for NF-kappaB activation in the airway epithelium in allergic airway disease and to unravel whether these signals are strain-dependent. Our previous studies, conducted in the BALB/c mouse background, demonstrated that transgenic mice expressing a dominant-negative version of IkappaBalpha in the airway epithelium (CC10-IkappaBalpha(SR)) were protected from Ova-induced inflammation. In contrast to these earlier observations, we demonstrate here that CC10-IkappaBalpha(SR) transgenic mice on the C57BL/6 background were not protected from Ova-induced allergic airway inflammation. Consistent with this finding, Ova-induced nuclear localization of the RelA subunit of NF-kappaB was not observed in C57BL/6 mice, in contrast to the marked nuclear presence of RelA in BALB/c mice. Evaluation of cytokine profiles in bronchoalveolar lavage demonstrated elevated expression of TNF-alpha in BALB/c mice compared with C57BL/6 mice after an acute challenge with Ova. Finally, neutralization of TNF-alpha by a blocking antibody prevented nuclear localization of RelA in BALB/c mice after Ova challenge. These data suggest that the mechanism of response of the airway epithelium of immunized C57BL/6 mice to antigen challenge is fundamentally different from that of immunized BALB/c mice and highlight the potential importance of TNF-alpha in regulating epithelial NF-kappaB activation in allergic airway disease. PMID:19897746

  6. Biological characteristics of tracheal smooth muscle cells regulated by NK-1R in asthmatic rat with airway remodeling

    PubMed Central

    Wei, Bing; Liu, Yali; Yue, Xiaozhe; Li, Yinping; Shang, Yunxiao

    2015-01-01

    This study aims to investigate the biological characteristic changes of infant rat tracheal smooth muscle cells in asthma airway remodeling and the impact of NK-1R on the mechanism. Ovalbumin (OVA) was used to excited juvenile SD rats by 8 w. Immunofluorescence, MTT assay, transwell chambers, real time quantitative PCR, Western blot and other methods were used to observe the proliferation, migration, synthesis and secretion changes of infant airway remodeling in rat tracheal smooth muscle cell and the Neurokinin 1 receptor (NK-1R) expression. 1. NK-1R mRNA, protein expression of airway smooth muscle cell (ASMC) of each asthma group were higher than that of the control group, especially the asthma 8 w group had highest expression (P<0.01). 2. The average A value of 8 w asthma group measured by MTT method were significantly higher than that of the control group (P<0.05), WIN62577 10-8 mol/L group had the strongest inhibition of ASMC proliferation (P<0.01). 3. The number of cell migration in the asthma group significantly increased than that in the control group. The number of migrating cells in the NK-1R antagonist group significantly reduced compared with the asthma 8 w group (P<0.05). 4. The average gray value of type III collagen in each asthma group were higher than that of the control group, and the asthma 8 w group had the highest (P<0.01). After NK-1R blocking, the average gray value of type III collagen was significantly lower (P<0.05). ASMC proliferation, migration, synthesis and secretion function increased in the airway remodeling group, and NK-1R played an important role. PMID:26628953

  7. Muscle hardness characteristics of the masseter muscle after repetitive muscle activation: comparison to the biceps brachii muscle.

    PubMed

    Kashima, Koji; Higashinaka, Shuichi; Watanabe, Naoshi; Maeda, Sho; Shiba, Ryosuke

    2004-10-01

    The purpose of this study was to compare hardness characteristics of the masseter muscle to those of the biceps brachii muscle during repetitive muscle movements. Seventeen asymptomatic female subjects participated in this study. Each subject, on separate days, undertook a 5-minute unilateral chewing gum task on the right side and a 5-minute flexion-extension exercise on the right hand with a 2kg dumbbell. Using a handheld hardness meter, muscle hardness was measured in the right masseter and in the biceps brachii muscle at eight time points (before the task, immediately after the task, and at 1, 3, 5, 10, 30, and 60 minutes after the task), and the data obtained before and after the task on each muscle were compared. Comparisons of the normalized data were also performed between the two muscles at each time point. As a result, a significant increase in muscle hardness was seen at 1 minute after the task in the biceps brachii muscle (p=0.0093). In contrast, the masseter muscle showed a tendency to lower hardness, with the lowest point of hardness occurring at 10 minutes after the task (p = 0.0160). Between the two muscles, there was a difference in the normalized data immediately after the task, and at 1, 5, and 10 minutes after the task (0.01 muscle hardness characteristics of the masseter muscle completely differed from those of the biceps brachii muscle after repetitive muscle activation. PMID:15532311

  8. Muscle activity characterization by laser Doppler Myography

    NASA Astrophysics Data System (ADS)

    Scalise, Lorenzo; Casaccia, Sara; Marchionni, Paolo; Ercoli, Ilaria; Primo Tomasini, Enrico

    2013-09-01

    Electromiography (EMG) is the gold-standard technique used for the evaluation of muscle activity. This technique is used in biomechanics, sport medicine, neurology and rehabilitation therapy and it provides the electrical activity produced by skeletal muscles. Among the parameters measured with EMG, two very important quantities are: signal amplitude and duration of muscle contraction, muscle fatigue and maximum muscle power. Recently, a new measurement procedure, named Laser Doppler Myography (LDMi), for the non contact assessment of muscle activity has been proposed to measure the vibro-mechanical behaviour of the muscle. The aim of this study is to present the LDMi technique and to evaluate its capacity to measure some characteristic features proper of the muscle. In this paper LDMi is compared with standard superficial EMG (sEMG) requiring the application of sensors on the skin of each patient. sEMG and LDMi signals have been simultaneously acquired and processed to test correlations. Three parameters has been analyzed to compare these techniques: Muscle activation timing, signal amplitude and muscle fatigue. LDMi appears to be a reliable and promising measurement technique allowing the measurements without contact with the patient skin.

  9. Bidirectional counter-regulation of human lung mast cell and airway smooth muscle β2-adrenoceptors

    PubMed Central

    Newby, Chris; Amrani, Yassine; Bradding, Peter

    2015-01-01

    Human lung mast cells (HLMCs) play a central role in asthma pathogenesis through their relocation to the airway smooth muscle (ASM) bundles. β2 adrenoceptor (β2-AR)-agonists are used to relieve bronchoconstriction in asthma, but may reduce asthma control, particularly when used as monotherapy. We hypothesised that HLMC and human ASM cell (HASMC) responsiveness to β2-AR agonists would be attenuated when HLMCs are in contact with HASMCs. Cells were cultured in the presence of the short-acting β2-agonist albuterol, and the long-acting β2-agonists formoterol and olodaterol. Constitutive and FcεRI-dependent HLMC histamine release, HASMC contraction, and β2-AR phosphorylation at tyrosine 350 (Tyr350) were assessed. Constitutive HLMC histamine release was increased in HLMC-HASMC co-culture and this was enhanced by β2-AR agonists. Inhibition of FcεRI-dependent HLMC mediator release by β2-agonists was greatly reduced in HLMC-HASMC co-culture. These effects were reversed by neutralisation of stem cell factor (SCF) or cell adhesion molecule 1 (CADM1). β2-AR agonists did not prevent HASMC contraction when HLMCs were present, but this was reversed by fluticasone. β2-AR phosphorylation at Tyr350 occurred within 5 minutes in both HLMCs and HASMCs when the cells were co-cultured, and was inhibited by neutralising SCF or CADM1. HLMC interactions with HASMCs via CADM1 and Kit inhibit the potentially beneficial effects of β2-AR agonists on these cells via phosphorylation of the β2-AR. These results may explain the potentially adverse effects of β2-ARs agonists when used for asthma therapy. Targeting SCF and CADM1 may enhance β2-AR efficacy, particularly in corticosteroid-resistant patients. PMID:26608913

  10. A deterministic model predicts the properties of stochastic calcium oscillations in airway smooth muscle cells.

    PubMed

    Cao, Pengxing; Tan, Xiahui; Donovan, Graham; Sanderson, Michael J; Sneyd, James

    2014-08-01

    The inositol trisphosphate receptor ([Formula: see text]) is one of the most important cellular components responsible for oscillations in the cytoplasmic calcium concentration. Over the past decade, two major questions about the [Formula: see text] have arisen. Firstly, how best should the [Formula: see text] be modeled? In other words, what fundamental properties of the [Formula: see text] allow it to perform its function, and what are their quantitative properties? Secondly, although calcium oscillations are caused by the stochastic opening and closing of small numbers of [Formula: see text], is it possible for a deterministic model to be a reliable predictor of calcium behavior? Here, we answer these two questions, using airway smooth muscle cells (ASMC) as a specific example. Firstly, we show that periodic calcium waves in ASMC, as well as the statistics of calcium puffs in other cell types, can be quantitatively reproduced by a two-state model of the [Formula: see text], and thus the behavior of the [Formula: see text] is essentially determined by its modal structure. The structure within each mode is irrelevant for function. Secondly, we show that, although calcium waves in ASMC are generated by a stochastic mechanism, [Formula: see text] stochasticity is not essential for a qualitative prediction of how oscillation frequency depends on model parameters, and thus deterministic [Formula: see text] models demonstrate the same level of predictive capability as do stochastic models. We conclude that, firstly, calcium dynamics can be accurately modeled using simplified [Formula: see text] models, and, secondly, to obtain qualitative predictions of how oscillation frequency depends on parameters it is sufficient to use a deterministic model. PMID:25121766

  11. Bidirectional Counterregulation of Human Lung Mast Cell and Airway Smooth Muscle β2 Adrenoceptors.

    PubMed

    Lewis, Rebecca J; Chachi, Latifa; Newby, Chris; Amrani, Yassine; Bradding, Peter

    2016-01-01

    Human lung mast cells (HLMCs) play a central role in asthma pathogenesis through their relocation to the airway smooth muscle (ASM) bundles. β2 adrenoceptor (β2-AR)-agonists are used to relieve bronchoconstriction in asthma, but may reduce asthma control, particularly when used as monotherapy. We hypothesized that HLMC and human ASM cell (HASMC) responsiveness to β2-AR agonists would be attenuated when HLMCs are in contact with HASMCs. Cells were cultured in the presence of the short-acting β2-agonist albuterol, and the long-acting β2-agonists formoterol and olodaterol. Constitutive and FcεRI-dependent HLMC histamine release, HASMC contraction, and β2-AR phosphorylation at Tyr(350) were assessed. Constitutive HLMC histamine release was increased in HLMC-HASMC coculture and this was enhanced by β2-AR agonists. Inhibition of FcεRI-dependent HLMC mediator release by β2-agonists was greatly reduced in HLMC-HASMC coculture. These effects were reversed by neutralization of stem cell factor (SCF) or cell adhesion molecule 1 (CADM1). β2-AR agonists did not prevent HASMC contraction when HLMCs were present, but this was reversed by fluticasone. β2-AR phosphorylation at Tyr(350) occurred within 5 min in both HLMCs and HASMCs when the cells were cocultured, and was inhibited by neutralizing SCF or CADM1. HLMC interactions with HASMCs via CADM1 and Kit inhibit the potentially beneficial effects of β2-AR agonists on these cells via phosphorylation of the β2-AR. These results may explain the potentially adverse effects of β2-ARs agonists when used for asthma therapy. Targeting SCF and CADM1 may enhance β2-AR efficacy, particularly in corticosteroid-resistant patients. PMID:26608913

  12. Acute response of airway muscle to extreme temperature includes disruption of actin-myosin interaction.

    PubMed

    Dyrda, Peter; Tazzeo, Tracy; DoHarris, Lindsay; Nilius, Berndt; Roman, Horia Nicolae; Lauzon, Anne-Marie; Aziz, Tariq; Lukic, Dusan; Janssen, Luke J

    2011-02-01

    Despite the emerging use of bronchial thermoplasty in asthma therapy, the response of airway smooth muscle (ASM) to extreme temperatures is unknown. We investigated the immediate effects of exposing ASM to supraphysiologic temperatures. Isometric contractions were studied in bovine ASM before and after exposure to various thermal loads and/or pharmacologic interventions. Actin-myosin interactions were investigated using a standard in vitro motility assay. We found steep thermal sensitivity for isometric contractions evoked by acetylcholine, with threshold and complete inhibition at less than 50°C and greater than 55°C, respectively. Contractile responses to serotonin or KCl were similarly affected, whereas isometric relaxations evoked by the nitric oxide donor S-nitrosyl-N-acetylpenicillamine or the β-agonist isoproterenol were unaffected. This thermal sensitivity developed within 15 minutes, but did not evolve further over the course of several days (such a rapid time-course rules out heat shock proteins, apoptosis, autophagy, and necrosis). Although heat-sensitive transient receptor potential (TRPV2) channels and the calmodulin-dependent (Cam) kinase-II-induced inactivation of myosin light chain kinase are both acutely thermally sensitive, with a temperature producing half-maximal effect (T(1/2)) of 52.5°C, the phenomenon we describe was not prevented by blockers of TRPV2 channels (e.g., ruthenium red, gadolinium, zero-Ca(2+) or zero-Na(+)/zero-Ca(2+) media, and cromakalim) or of Cam kinase-II (e.g., W7, trifluoperazine, and KN-93). However, direct measurements of actin-myosin interactions showed the same steep thermal profile. The functional changes preceded any histologic evidence of necrosis or apoptosis. We conclude that extreme temperatures (such as those used in bronchial thermoplasty) directly disrupt actin-myosin interactions, likely through a denaturation of the motor protein, leading to an immediate loss of ASM cell function. PMID:20395634

  13. Forelimb muscle activity during equine locomotion.

    PubMed

    Harrison, Simon M; Whitton, R Chris; King, Melissa; Haussler, Kevin K; Kawcak, Chris E; Stover, Susan M; Pandy, Marcus G

    2012-09-01

    Few quantitative data exist to describe the activity of the distal muscles of the equine forelimb during locomotion, and there is an incomplete understanding of the functional roles of the majority of the forelimb muscles. Based on morphology alone it would appear that the larger proximal muscles perform the majority of work in the forelimb, whereas the smaller distal muscles fulfil supplementary roles such as stabilizing the joints and positioning the limb for impact with the ground. We measured the timing and amplitude of the electromyographic activity of the intrinsic muscles of the forelimb in relation to the phase of gait (stance versus swing) and the torque demand placed on each joint during walking, trotting and cantering. We found that all forelimb muscles, except the extensor carpi radialis (ECR), were activated just prior to hoof-strike and deactivated during stance. Only the ECR was activated during swing. The amplitudes of muscle activation typically increased as gait speed increased. However, the amplitudes of muscle activation were not proportional to the net joint torques, indicating that passive structures may also contribute significantly to torque generation. Our results suggest that the smaller distal muscles help to stabilize the forelimb in early stance, in preparation for the passive structures (tendons and ligaments) to be stretched. The distal forelimb muscles remain active throughout stance only during canter, when the net torques acting about the distal forelimb joints are highest. The larger proximal muscles activate in a complex coordination to position and stabilize the shoulder and elbow joints during ground contact. PMID:22875767

  14. Real-time imaging of ATP release induced by mechanical stretch in human airway smooth muscle cells.

    PubMed

    Takahara, Norihiro; Ito, Satoru; Furuya, Kishio; Naruse, Keiji; Aso, Hiromichi; Kondo, Masashi; Sokabe, Masahiro; Hasegawa, Yoshinori

    2014-12-01

    Airway smooth muscle (ASM) cells within the airway walls are continually exposed to mechanical stimuli, and exhibit various functions in response to these mechanical stresses. ATP acts as an extracellular mediator in the airway. Moreover, extracellular ATP is considered to play an important role in the pathophysiology of asthma and chronic obstructive pulmonary disease. However, it is not known whether ASM cells are cellular sources of ATP secretion in the airway. We therefore investigated whether mechanical stretch induces ATP release from ASM cells. Mechanical stretch was applied to primary human ASM cells cultured on a silicone chamber coated with type I collagen using a stretching apparatus. Concentrations of ATP in cell culture supernatants measured by luciferin-luciferase bioluminescence were significantly elevated by cyclic stretch (12 and 20% strain). We further visualized the stretch-induced ATP release from the cells in real time using a luminescence imaging system, while acquiring differential interference contrast cell images with infrared optics. Immediately after a single uniaxial stretch for 1 second, strong ATP signals were produced by a certain population of cells and spread to surrounding spaces. The cyclic stretch-induced ATP release was significantly reduced by inhibitors of Ca(2+)-dependent vesicular exocytosis, 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetraacetoxymethyl ester, monensin, N-ethylmaleimide, and bafilomycin. In contrast, the stretch-induced ATP release was not inhibited by a hemichannel blocker, carbenoxolone, or blockade of transient receptor potential vanilloid 4 by short interfering RNA transfection or ruthenium red. These findings reveal a novel property of ASM cells: mechanically induced ATP release may be a cellular source of ATP in the airway. PMID:24885163

  15. YAP is up-regulated in the bronchial airway smooth muscle of the chronic asthma mouse model.

    PubMed

    Zhou, Jing; Xu, Fei; Yu, Jing Jing; Zhang, Wei

    2015-01-01

    Asthma is characterized by leukocytic infiltration and tissue remodeling with structural changes including subepithelial fibrosis and ASM cells proliferation. The Hippo pathway is a key regulatory point involved in cell proliferation, fibroblasts, and smooth muscle cell differentiation. In order to disclose the relation between asthma and the Hippo pathway, expression of the Yes-associated protein (YAP), a key gene in the Hippo pathway, in the bronchial smooth muscle of chronic asthma model (CAM) was studied. 40 mice were randomly divided into control (wide type) and experimental group to construct CAM using chicken ovalbumin (OVA). Pathological changes of the lung tissues were observed in the CAM mice compared with the control using HE staining method. Immunohistochemistry (IHC) was used to detect if YAP protein is expressed in the lung tissues. The pathological changes of the CAM group showed that a large number of inflammatory cells infiltration including mainly lymphocytes and a small amount of eosinophilic, with the presence of certain airway smooth muscle hyperplasia, was observed in comparison with the control. IHC results showed that the YAP protein was significantly increased compared with the control groups (P < 0.01). This result was further confirmed by quantitative real-time PCR (qPCR) assay which detected the up-regulation of the YAP gene (P < 0.01) and Western blot. In conclusion, the YAP protein was significantly expressed in the bronchial airway tissues of the CAM mice, and could be used as an indicator for asthma. PMID:26617833

  16. Airway Peroxidases Catalyze Nitration of the β2-Agonist Salbutamol and Decrease Its Pharmacological Activity

    PubMed Central

    Sallans, Larry; Macha, Stephen; Brown, Kari; McGraw, Dennis W.; Kovacic, Melinda Butsch; Britigan, Bradley E.

    2011-01-01

    β2-Agonists are the most effective bronchodilators for the rapid relief of asthma symptoms, but for unclear reasons, their effectiveness may be decreased during severe exacerbations. Because peroxidase activity and nitrogen oxides are increased in the asthmatic airway, we examined whether salbutamol, a clinically important β2-agonist, is subject to potentially inactivating nitration. When salbutamol was exposed to myeloperoxidase, eosinophil peroxidase or lactoperoxidase in the presence of hydrogen peroxide (H2O2) and nitrite (NO2−), both absorption spectroscopy and mass spectrometry indicated formation of a new metabolite with features expected for the nitrated drug. The new metabolites showed an absorption maximum at 410 nm and pKa of 6.6 of the phenolic hydroxyl group. In addition to nitrosalbutamol (m/z 285.14), a salbutamol-derived nitrophenol, formed by elimination of the formaldehyde group, was detected (m/z 255.13) by mass spectrometry. It is noteworthy that the latter metabolite was detected in exhaled breath condensates of asthma patients receiving salbutamol but not in unexposed control subjects, indicating the potential for β2-agonist nitration to occur in the inflamed airway in vivo. Salbutamol nitration was inhibited in vitro by ascorbate, thiocyanate, and the pharmacological agents methimazole and dapsone. The efficacy of inhibition depended on the nitrating system, with the lactoperoxidase/H2O2/NO2− being the most affected. Functionally, nitrated salbutamol showed decreased affinity for β2-adrenergic receptors and impaired cAMP synthesis in airway smooth muscle cells compared with the native drug. These results suggest that under inflammatory conditions associated with asthma, phenolic β2-agonists may be subject to peroxidase-catalyzed nitration that could potentially diminish their therapeutic efficacy. PMID:20974700

  17. Selective visualisation of sensory receptors in the smooth muscle layer of ex-vivo airway whole-mounts by styryl pyridinium dyes.

    PubMed

    De Proost, Ian; Pintelon, Isabel; Brouns, Inge; Timmermans, Jean-Pierre; Adriaensen, Dirk

    2007-09-01

    Recently, we established the location, morphology and neurochemical coding of vagal smooth-muscle-associated airway receptors (SMARs) in rat lungs. These receptors were characterised as branching laminar terminals that originated from myelinated nerve fibres and were intercalated between airway smooth-muscle bundles. To allow the direct physiological examination of these receptors, the present investigation aimed at visualising SMARs in airway whole-mounts of rat and mouse lungs ex vivo. Short incubation with various styryl pyridinium dyes (AM1-43, FM2-10, FM4-64 or 4-Di-2-ASP) gave a highly selective fluorescent visualisation of both laminar nerve terminals and myelinated fibres from which they originated throughout the intrapulmonary airway tree in mouse and in rat. The reliable and specific labelling of SMARs ex vivo with these lipophilic membrane dyes was confirmed via immunostaining for protein gene-product 9.5 and vesicular glutamate transporters. Similar to the intrapulmonary location of NEBs, these SMARs appeared to be even more explicitly located near airway bifurcations. Both the trachealis muscle and the smooth-muscle bundles of extrapulmonary bronchi were also shown to contain laminar nerve terminals that were morphologically similar to the SMARs reported in the intrapulmonary airways. Thus, this study provides an in-vitro model enabling, for the first time, the fast and reliable visualisation of SMARs and the myelinated nerve fibres from which they originate in airway whole-mount preparations ex vivo. As such, this model opens up further perspectives and creates a valid basis for direct physiological measurement and manipulation of the individually identified airway receptors. PMID:17522895

  18. CXCL8 histone H3 acetylation is dysfunctional in airway smooth muscle in asthma: regulation by BET

    PubMed Central

    Clifford, Rachel L.; Patel, Jamie K.; John, Alison E.; Tatler, Amanda L.; Mazengarb, Lisa; Brightling, Christopher E.

    2015-01-01

    Asthma is characterized by airway inflammation and remodeling and CXCL8 is a CXC chemokine that drives steroid-resistant neutrophilic airway inflammation. We have shown that airway smooth muscle (ASM) cells isolated from asthmatic individuals secrete more CXCL8 than cells from nonasthmatic individuals. Here we investigated chromatin modifications at the CXCL8 promoter in ASM cells from nonasthmatic and asthmatic donors to further understand how CXCL8 is dysregulated in asthma. ASM cells from asthmatic donors had increased histone H3 acetylation, specifically histone H3K18 acetylation, and increased binding of histone acetyltransferase p300 compared with nonasthmatic donors but no differences in CXCL8 DNA methylation. The acetylation reader proteins Brd3 and Brd4 were bound to the CXCL8 promoter and Brd inhibitors inhibited CXCL8 secretion from ASM cells by disrupting Brd4 and RNA polymerase II binding to the CXCL8 promoter. Our results show a novel dysregulation of CXCL8 transcriptional regulation in asthma characterized by a promoter complex that is abnormal in ASM cells isolated from asthmatic donors and can be modulated by Brd inhibitors. Brd inhibitors may provide a new therapeutic strategy for steroid-resistant inflammation. PMID:25713319

  19. Arachidonate-Regulated Ca2+ Influx in Human Airway Smooth Muscle

    PubMed Central

    Thompson, Michael A.; Prakash, Y. S.

    2014-01-01

    Plasma membrane Ca2+ influx, especially store-operated Ca2+ entry triggered by sarcoplasmic reticulum (SR) Ca2+ release, is a key component of intracellular calcium concentration ([Ca2+]i) regulation in airway smooth muscle (ASM). Agonist-induced Ca2+ oscillations in ASM that involve both influx and SR mechanisms have been previously demonstrated. In nonexcitable cells, [Ca2+]i oscillations involve Ca2+ influx via arachidonic acid (AA) –stimulated channels, which show similarities to store-operated Ca2+ entry, although their molecular identity remains undetermined. Little is known about AA-regulated Ca2+ channels or their regulation in ASM. In enzymatically dissociated human ASM cells loaded with the Ca2+ indicator, fura-2, AA (1–10 μM) triggered [Ca2+]i oscillations that were inhibited by removal of extracellular Ca2+. Other fatty acids, such as the diacylglycerol analog, 1-oleoyl-2-acetyl-SN-glycerol, oleic acid, and palmitic acid (10 μM each), failed to elicit similar [Ca2+]i responses. Preincubation with LaCl3 (1 μM or 1 mM) inhibited AA-induced oscillations. Inhibition of receptor-operated channels (SKF96,365 [10 μM]), lipoxygenase (zileuton [10 μM]), or cyclooxygenase (indomethacin [10 μM]) did not affect oscillation parameters. Inhibition of SR Ca2+ release (ryanodine [10 μM] or inositol 1,4,5-trisphosphate receptor inhibitor, xestospongin C [1 μM]) decreased [Ca2+]i oscillation frequency and amplitude. Small interfering RNA against caveolin-1, stromal interaction molecule 1, or Orai3 (20 nM each) reduced the frequency and amplitude of AA-induced [Ca2+]i oscillations. In ASM cells derived from individuals with asthma, AA increased oscillation amplitude, but not frequency. These results are highly suggestive of a novel AA-mediated Ca2+–regulatory mechanism in human ASM, reminiscent of agonist-induced oscillations. Given the role of AA in ASM intracellular signaling, especially with inflammation, AA-regulated Ca2+ channels could potentially

  20. Microgravity effects on 'postural' muscle activity patterns

    NASA Technical Reports Server (NTRS)

    Layne, Charles S.; Spooner, Brian S.

    1994-01-01

    Changes in neuromuscular activation patterns associated with movements made in microgravity can contribute to muscular atrophy. Using electromyography (EMG) to monitor 'postural' muscles, it was found that free floating arm flexions made in microgravity were not always preceded by neuromuscular activation patterns normally observed during movements made in unit gravity. Additionally, manipulation of foot sensory input during microgravity arm flexion impacted upon anticipatory postural muscle activation.

  1. Protective effects of anisodamine on cigarette smoke extract-induced airway smooth muscle cell proliferation and tracheal contractility

    SciTech Connect

    Xu, Guang-Ni; Yang, Kai; Xu, Zu-Peng; Zhu, Liang; Hou, Li-Na; Qi, Hong; Chen, Hong-Zhuan Cui, Yong-Yao

    2012-07-01

    Anisodamine, an antagonist of muscarinic acetylcholine receptors (mAChRs), has been used therapeutically to improve smooth muscle function, including microvascular, intestinal and airway spasms. Our previous studies have revealed that airway hyper-reactivity could be prevented by anisodamine. However, whether anisodamine prevents smoking-induced airway smooth muscle (ASM) cell proliferation remained unclear. In this study, a primary culture of rat ASM cells was used to evaluate an ASM phenotype through the ability of the cells to proliferate and express contractile proteins in response to cigarette smoke extract (CSE) and intervention of anisodamine. Our results showed that CSE resulted in an increase in cyclin D1 expression concomitant with the G0/G1-to-S phase transition, and high expression of M2 and M3. Functional studies showed that tracheal hyper-contractility accompanied contractile marker α-SMA high-expression. These changes, which occur only after CSE stimulation, were prevented and reversed by anisodamine, and CSE-induced cyclin D1 expression was significantly inhibited by anisodamine and the specific inhibitor U0126, BAY11-7082 and LY294002. Thus, we concluded that the protective and reversal effects and mechanism of anisodamine on CSE-induced events might involve, at least partially, the ERK, Akt and NF-κB signaling pathways associated with cyclin D1 via mAChRs. Our study validated that anisodamine intervention on ASM cells may contribute to anti-remodeling properties other than bronchodilation. -- Highlights: ► CSE induces tracheal cell proliferation, hyper-contractility and α-SMA expression. ► Anisodamine reverses CSE-induced tracheal hyper-contractility and cell proliferation. ► ERK, PI3K, and NF-κB pathways and cyclin D1 contribute to the reversal effect.

  2. Influence of genioglossus tonic activity on upper airway dynamics assessed by phrenic nerve stimulation.

    PubMed

    Sériès, F; Marc, I

    2002-01-01

    Upper airway (UA) dynamics can be evaluated during wakefulness by using electrical phrenic nerve stimulation (EPNS) applied at end-expiration during exclusive nasal breathing by dissociating twitch flow and phasic activation of UA muscles. This technique can be used to quantify the influence of nonphasic electromyographic (EMG) activity on UA dynamics. UA dynamics was characterized by using EPNS when increasing tonic EMG activity with CO(2) stimulation in six normal awake subjects. Instantaneous flow, esophageal and nasopharyngeal pressures, and genioglossal EMG activity were recorded during EPNS at baseline and during CO(2) ventilatory stimulation. The proportion of twitches presenting an inspiratory-flow limitation pattern decreased from 100% at baseline to 78.7 +/- 21.4% (P = 10(-4)) during CO(2) rebreathing. During CO(2) stimuli, maximal inspiratory twitch flow (VI(max)) of flow-limited twitches significantly rose, with the driving pressure at which flow limitation occurred being more negative. For the group as a whole, the increase in VI(max) and the decrease in pressure were significantly correlated with the rise in end-expiratory EMG activity. UA stability assessed by EPNS is dramatically modified during CO(2) ventilatory stimulation. Changes in tonic genioglossus EMG activity significantly contribute to the improvement in UA stability. PMID:11744686

  3. KCNQ (Kv7) potassium channel activators as bronchodilators: combination with a β2-adrenergic agonist enhances relaxation of rat airways.

    PubMed

    Brueggemann, Lioubov I; Haick, Jennifer M; Neuburg, Samantha; Tate, Shawn; Randhawa, Devjit; Cribbs, Leanne L; Byron, Kenneth L

    2014-03-15

    KCNQ (Kv7 family) potassium (K(+)) channels were recently found in airway smooth muscle cells (ASMCs) from rodent and human bronchioles. In the present study, we evaluated expression of KCNQ channels and their role in constriction/relaxation of rat airways. Real-time RT-PCR analysis revealed expression of KCNQ4 > KCNQ5 > KCNQ1 > KCNQ2 > KCNQ3, and patch-clamp electrophysiology detected KCNQ currents in rat ASMCs. In precision-cut lung slices, the KCNQ channel activator retigabine induced a concentration-dependent relaxation of small bronchioles preconstricted with methacholine (MeCh; EC50 = 3.6 ± 0.3 μM). Bronchoconstriction was also attenuated in the presence of two other structurally unrelated KCNQ channel activators: zinc pyrithione (ZnPyr; 1 μM; 22 ± 7%) and 2,5-dimethylcelecoxib (10 μM; 24 ± 8%). The same three KCNQ channel activators increased KCNQ currents in ASMCs by two- to threefold. The bronchorelaxant effects of retigabine and ZnPyr were prevented by inclusion of the KCNQ channel blocker XE991. A long-acting β2-adrenergic receptor agonist, formoterol (10 nM), did not increase KCNQ current amplitude in ASMCs, but formoterol (1-1,000 nM) did induce a time- and concentration-dependent relaxation of rat airways, with a notable desensitization during a 30-min treatment or with repetitive treatments. Coadministration of retigabine (10 μM) with formoterol produced a greater peak and sustained reduction of MeCh-induced bronchoconstriction and reduced the apparent desensitization observed with formoterol alone. Our findings support a role for KCNQ K(+) channels in the regulation of airway diameter. A combination of a β2-adrenergic receptor agonist with a KCNQ channel activator may improve bronchodilator therapy. PMID:24441871

  4. Effect of the plant derivative Compound A on the production of corticosteroid-resistant chemokines in airway smooth muscle cells.

    PubMed

    Gavrila, Adelina; Chachi, Latifa; Tliba, Omar; Brightling, Christopher; Amrani, Yassine

    2015-11-01

    Preclinical models of human conditions including asthma showed the therapeutic potential of Compound A (CpdA), a dissociated glucocorticoid (GC) receptor (GRα) ligand. Whether CpdA inhibits GC resistance, a central feature of severe asthma, has not been addressed. We investigated whether CpdA modulates cytokine-induced GC resistance in human airway smooth muscle (ASM) cells. Healthy and asthmatic ASM cells were treated with TNF-α/IFN-γ for 24 hours in the presence or absence of CpdA. ELISA and quantitative PCR assays were used to assess the effect of CpdA on chemokine expression. Activation of GRα by CpdA was assessed by quantitative PCR, immunostaining, and receptor antagonism using RU486. An effect of CpdA on the transcription factor interferon regulatory factor 1 (IRF-1) was investigated using immunoblot, immunostaining, and small interfering RNA (siRNA) knockdown. CpdA inhibited production of fluticasone-resistant chemokines CCL5, CX3CL1, and CXCL10 at protein and mRNA levels in both asthmatic and healthy cells. CpdA failed to induce expression of GC-induced Leucine Zipper while transiently inducing mitogen-activated protein kinase phosphatase 1 (MKP-1) at both mRNA and protein levels. CpdA inhibitory action was not associated with GRα nuclear translocation, nor was it prevented by RU486 antagonism. Activation of IRF-1 by TNF-α/IFN-γ was inhibited by CpdA. IRF-1 siRNA knockdown reduced cytokine-induced CCL5 and CX3CL1 production. siRNA MKP-1 prevented the inhibitory effect of CpdA on cytokine-induced CXCL10 production. For the first time, we show that CpdA inhibits the production of GC-resistant chemokines via GRα-independent mechanisms involving the inhibition of IRF-1 and up-regulation of MKP-1. Thus, targeting CpdA-sensitive pathways in ASM cells represents an alternative therapeutic approach to treat GC resistance in asthma. PMID:25897650

  5. Effect of subchronic in vivo exposure to nitrogen dioxide on lung tissue inflammation, airway microvascular leakage, and in vitro bronchial muscle responsiveness in rats.

    PubMed Central

    Chitano, P; Rado, V; Di Stefano, A; Papi, A; Boniotti, A; Zancuoghi, G; Boschetto, P; Romano, M; Salmona, M; Ciaccia, A; Fabbri, L M; Mapp, C E

    1996-01-01

    OBJECTIVES: In a previous study on bronchoalveolar lavage fluid from rats exposed in vivo for seven days to 10 ppm nitrogen dioxide (NO2), it has been shown that there is an influx of macrophages into the airways. The present study investigated the effect of seven day exposure to 10 ppm NO2, on: (a) lung tissue inflammation and morphology; (b) airway microvascular leakage; (c) in vitro contractile response of main bronchi. METHODS: Lung tissue was studied by light microscopy, after fixing the lungs by inflation with 4% formalin at a pressure of 20 cm H2O. Microvascular leakage was measured by extravasation of Evans blue dye in the larynx, trachea, main bronchi, and intrapulmonary airways. Smooth muscle responsiveness was evaluated by concentration-responses curves to acetylcholine (10(-9)-10(-3) M), serotonin (10(-9)-10(-4) M), and voltage-response curves (12-28 V) to electrical field stimulation. RESULTS: Histology showed an increased total inflammation at the level of respiratory bronchioles and alveoli. No influx of inflammatory cells was found in the main bronchi. A loss of cilia in the epithelium of small airways and ectasia of alveolar capillaries was also found. By contrast, no alterations to microvascular permeability or modification of bronchial smooth muscle responsiveness was found. CONCLUSIONS: Subchronic exposure to 10 ppm NO2 causes airway inflammation and structural damage, but does not cause any persistent alteration to microvascular permeability or bronchial smooth muscle responsiveness in rats. Images Figure 1 PMID:8758032

  6. Airway Epithelial NF-κB Activation Promotes Mycoplasma pneumoniae Clearance in Mice

    PubMed Central

    Jiang, Di; Nelson, Mark L.; Gally, Fabienne; Smith, Sean; Wu, Qun; Minor, Maisha; Case, Stephanie; Thaikoottathil, Jyoti; Chu, Hong Wei

    2012-01-01

    Background/Objective Respiratory infections including atypical bacteria Mycoplasma pneumoniae (Mp) contribute to the pathobiology of asthma and chronic obstructive pulmonary disease (COPD). Mp infection mainly targets airway epithelium and activates various signaling pathways such as nuclear factor κB (NF-κB). We have shown that short palate, lung, and nasal epithelium clone 1 (SPLUNC1) serves as a novel host defense protein and is up-regulated upon Mp infection through NF-κB activation in cultured human and mouse primary airway epithelial cells. However, the in vivo role of airway epithelial NF-κB activation in host defense against Mp infection has not been investigated. In the current study, we investigated the effects of in vivo airway epithelial NF-κB activation on lung Mp clearance and its association with airway epithelial SPLUNC1 expression. Methodology/Main Results Non-antimicrobial tetracycline analog 9-t-butyl doxycycline (9-TB) was initially optimized in mouse primary tracheal epithelial cell culture, and then utilized to induce in vivo airway epithelial specific NF-κB activation in conditional NF-κB transgenic mice (CC10-CAIKKβ) with or without Mp infection. Lung Mp load and inflammation were evaluated, and airway epithelial SPLUNC1 protein was examined by immunohistochemistry. We found that 9-TB treatment in NF-κB transgene positive (Tg+), but not transgene negative (Tg−) mice significantly reduced lung Mp load. Moreover, 9-TB increased airway epithelial SPLUNC1 protein expression in NF-κB Tg+ mice. Conclusion By using the non-antimicrobial 9-TB, our study demonstrates that in vivo airway epithelial NF-κB activation promotes lung bacterial clearance, which is accompanied by increased epithelial SPLUNC1 expression. PMID:23285237

  7. Immunomodulation of airway epithelium cell activation by mesenchymal stromal cells ameliorates house dust mite-induced airway inflammation in mice.

    PubMed

    Duong, Khang M; Arikkatt, Jaisy; Ullah, M Ashik; Lynch, Jason P; Zhang, Vivian; Atkinson, Kerry; Sly, Peter D; Phipps, Simon

    2015-11-01

    Allergic asthma is underpinned by T helper 2 (Th2) inflammation. Redundancy in Th2 cytokine function and production by innate and adaptive immune cells suggests that strategies aimed at immunomodulation may prove more beneficial. Hence, we sought to determine whether administration of mesenchymal stromal cells (MSCs) to house dust mite (HDM) (Dermatophagoides pteronyssinus)-sensitized mice would suppress the development of Th2 inflammation and airway hyperresponsiveness (AHR) after HDM challenge. We report that the intravenous administration of allogeneic donor MSCs 1 hour before allergen challenge significantly attenuated the features of allergic asthma, including tissue eosinophilia, Th2 cytokine (IL-5 and IL-13) levels in bronchoalveolar lavage fluid, and AHR. The number of infiltrating type 2 innate lymphoid cells was not affected by MSC transfer, suggesting that MSCs may modulate the adaptive arm of Th2 immunity. The effect of MSC administration was long lasting; all features of allergic airway disease were significantly suppressed in response to a second round of HDM challenge 4 weeks after MSC administration. Further, we observed that MSCs decreased the release of epithelial cell-derived alarmins IL-1α and high mobility group box-1 in an IL-1 receptor antagonist-dependent manner. This significantly decreased the expression of the pro-Th2 cytokine IL-25 and reduced the number of activated and antigen-acquiring CD11c(+)CD11b(+) dendritic cells in the lung and mediastinal lymph nodes. Our findings suggest that MSC administration can ameliorate allergic airway inflammation by blunting the amplification of epithelial-derived inflammatory cytokines induced by HDM exposure and may offer long-term protection against Th2-mediated allergic airway inflammation and AHR. PMID:25789608

  8. [Muscle enzyme activity and exercise].

    PubMed

    Gojanovic, B; Feihl, F; Gremion, G; Waeber, B

    2009-02-01

    Exercise is classically associated with muscular soreness, presenting one to two days later, delayed onset muscular soreness. Blood muscle enzymes and protein elevations are characteristic, and may cause renal failure. Creatin phosphokinase peak appears on the fourth day and depends on exercise type and individual parameters. This effect is attenuated with repeated bouts, by habituation. Metabolic complications are rare. The knowledge of this reaction, even with common exercises, allows to postpone investigations for a complex metabolic disorder, or to avoid stopping a medication for fear of a side effect, as with statins. Indeed, it is necessary to wait for seven days without any exercise before interpreting an elevated CK result. PMID:19180440

  9. Differentiated muscles are mandatory for gas-filling of the Drosophila airway system

    PubMed Central

    Wang, Yiwen; Cruz, Tina; Irion, Uwe; Moussian, Bernard

    2015-01-01

    ABSTRACT At the end of development, organs acquire functionality, thereby ensuring autonomy of an organism when it separates from its mother or a protective egg. In insects, respiratory competence starts when the tracheal system fills with gas just before hatching of the juvenile animal. Cellular and molecular mechanisms of this process are not fully understood. Analyses of the phenotype of Drosophila embryos with malformed muscles revealed that they fail to gas-fill their tracheal system. Indeed, we show that major regulators of muscle formation like Lame duck and Blown fuse are important, while factors involved in the development of subsets of muscles including cardiac and visceral muscles are dispensable for this process, suggesting that somatic muscles (or parts of them) are essential to enable tracheal terminal differentiation. Based on our phenotypic data, we assume that somatic muscle defect severity correlates with the penetrance of the gas-filling phenotype. This argues that a limiting molecular or mechanical muscle-borne signal tunes tracheal differentiation. We think that in analogy to the function of smooth muscles in vertebrate lungs, a balance of physical forces between muscles and the elasticity of tracheal walls may be decisive for tracheal terminal differentiation in Drosophila. PMID:26621831

  10. Oxidative stress–induced mitochondrial dysfunction drives inflammation and airway smooth muscle remodeling in patients with chronic obstructive pulmonary disease

    PubMed Central

    Wiegman, Coen H.; Michaeloudes, Charalambos; Haji, Gulammehdi; Narang, Priyanka; Clarke, Colin J.; Russell, Kirsty E.; Bao, Wuping; Pavlidis, Stelios; Barnes, Peter J.; Kanerva, Justin; Bittner, Anton; Rao, Navin; Murphy, Michael P.; Kirkham, Paul A.; Chung, Kian Fan; Adcock, Ian M.; Brightling, Christopher E.; Davies, Donna E.; Finch, Donna K.; Fisher, Andrew J.; Gaw, Alasdair; Knox, Alan J.; Mayer, Ruth J.; Polkey, Michael; Salmon, Michael; Singh, David

    2015-01-01

    Background Inflammation and oxidative stress play critical roles in patients with chronic obstructive pulmonary disease (COPD). Mitochondrial oxidative stress might be involved in driving the oxidative stress–induced pathology. Objective We sought to determine the effects of oxidative stress on mitochondrial function in the pathophysiology of airway inflammation in ozone-exposed mice and human airway smooth muscle (ASM) cells. Methods Mice were exposed to ozone, and lung inflammation, airway hyperresponsiveness (AHR), and mitochondrial function were determined. Human ASM cells were isolated from bronchial biopsy specimens from healthy subjects, smokers, and patients with COPD. Inflammation and mitochondrial function in mice and human ASM cells were measured with and without the presence of the mitochondria-targeted antioxidant MitoQ. Results Mice exposed to ozone, a source of oxidative stress, had lung inflammation and AHR associated with mitochondrial dysfunction and reflected by decreased mitochondrial membrane potential (ΔΨm), increased mitochondrial oxidative stress, and reduced mitochondrial complex I, III, and V expression. Reversal of mitochondrial dysfunction by the mitochondria-targeted antioxidant MitoQ reduced inflammation and AHR. ASM cells from patients with COPD have reduced ΔΨm, adenosine triphosphate content, complex expression, basal and maximum respiration levels, and respiratory reserve capacity compared with those from healthy control subjects, whereas mitochondrial reactive oxygen species (ROS) levels were increased. Healthy smokers were intermediate between healthy nonsmokers and patients with COPD. Hydrogen peroxide induced mitochondrial dysfunction in ASM cells from healthy subjects. MitoQ and Tiron inhibited TGF-β–induced ASM cell proliferation and CXCL8 release. Conclusions Mitochondrial dysfunction in patients with COPD is associated with excessive mitochondrial ROS levels, which contribute to enhanced inflammation and cell

  11. Abnormal Histone Methylation is Responsible for Increased VEGF165a Secretion from Airway Smooth Muscle Cells in Asthma

    PubMed Central

    Clifford, Rachel L.; John, Alison E.; Brightling, Christopher E.; Knox, Alan J.

    2012-01-01

    Vascular Endothelial Growth Factor (VEGF), a key angiogenic molecule, is aberrantly expressed in several diseases including asthma where it contributes to bronchial vascular remodelling and chronic inflammation. Asthmatic human airway smooth muscle (HASM) cells hypersecrete VEGF but the mechanism is unclear. Here we defined the mechanism in HASM cells from non-asthmatic (NA) and asthmatic (A) patients. We found that asthmatic cells lacked a repression complex at the VEGF promoter which was present in non-asthmatic cells. Recruitment of G9A, trimethylation of histone H3 at lysine 9 (H3K9me3) and a resultant decrease in RNA polymerase II (RNA pol II) at the VEGF promoter was critical to repression of VEGF secretion in non-asthmatic cells. At the asthmatic promoter H3K9me3 was absent due to failed recruitment of G9a; RNA pol II binding, in association with TAF1, was increased, H3K4me3 was present and Sp1 binding was exaggerated and sustained. In contrast DNA methylation and histone acetylation were similar in A and NA cells. This is the first study to show that airway cells in asthma have altered epigenetic regulation of remodelling gene(s). Histone methylation at genes such as VEGF may be an important new therapeutic target. PMID:22689881

  12. In vivo recording of electrical activity of canine tracheal smooth muscle.

    PubMed

    Kondo, T; Tamura, K; Onoe, K; Takahira, H; Ohta, Y; Yamabayashi, H

    1992-01-01

    Electrical activity of the tracheal smooth muscle was studied using extracellular bipolar electrodes in 37 decerebrate, paralyzed, and mechanically ventilated dogs. A spontaneous oscillatory potential that consisted of a slow sinusoidal wave of 0.57 +/- 0.13 (SD) Hz mean frequency but lacked a fast spike component was recorded from 15 dogs. Lung collapse accomplished by bilateral pneumothoraxes evoked or augmented the slow potentials that were associated with an increase in tracheal muscle contraction in 26 dogs. This suggests that the inputs from the airway mechanoreceptors reflexly activate the tracheal smooth muscle cells. Bilateral vagal transection abolished both the spontaneous and the reflexly evoked slow waves and provided relaxation of the tracheal smooth muscle. Electrical stimulation of the distal nerve with a train pulse (0.5 ms, 1-30 Hz) evoked slow-wave oscillatory potentials accompanied by a contraction of the tracheal smooth muscle in all the experimental animals. Our observations in this in vivo study confirm that the electrical activity of tracheal smooth muscle consists of slow oscillatory potentials and that tracheal contraction is at least partly coupled to the slow-wave activity of the smooth muscle. PMID:1537706

  13. [Role of bronchodilators in therapy for COPD-mechanisms of LABA and LAMA on airway smooth muscle].

    PubMed

    Kume, Hiroaki

    2016-05-01

    Long-acting β2-adrenergic receptor agonists (LABAs) and anticholinergics (LAMAs) are widely used clinically as therpy for COPD. Clinical reports have demonstrated that LABAs (salmeterol, formoterol, indacaterol, olodaterol, vilanterol) and LAMAs (tiotropium, glycopyrronium, umeclidinium, aclidinium) are useful to improving symptoms and lung function, and to reducing exacerbation and hospitarization. LABAs expect salmeterol are strong partial agonists, and LAMAs are non-specific antagonists. Ca2+ dynamics and Ca2+ sensitization contribute to relaxation of airway smooth muscle in these bronchodilators. LABAs act on orthosteric and allosteric sites on the β2-adrenergic receptors. In contrast, LAMAs act not only on orthosteric site on the muscarinic receptors, but also allosteric site on the β2-adrenergic receptors, leading to enhancing β2-adrenergic action. Allosteric GPCR modulation is involved in the synergistic effects between LABAs and LAMAs. PMID:27254952

  14. Muscle metaboreflex activation during dynamic exercise vasoconstricts ischemic active skeletal muscle.

    PubMed

    Kaur, Jasdeep; Machado, Tiago M; Alvarez, Alberto; Krishnan, Abhinav C; Hanna, Hanna W; Altamimi, Yasir H; Senador, Danielle; Spranger, Marty D; O'Leary, Donal S

    2015-12-15

    Metabolite accumulation due to ischemia of active skeletal muscle stimulates group III/IV chemosensitive afferents eliciting reflex increases in arterial blood pressure and sympathetic activity, termed the muscle metaboreflex. We and others have previously demonstrated sympathetically mediated vasoconstriction of coronary, renal, and forelimb vasculatures with muscle metaboreflex activation (MMA). Whether MMA elicits vasoconstriction of the ischemic muscle from which it originates is unknown. We hypothesized that the vasodilation in active skeletal muscle with imposed ischemia becomes progressively restrained by the increasing sympathetic vasoconstriction during MMA. We activated the metaboreflex during mild dynamic exercise in chronically instrumented canines via graded reductions in hindlimb blood flow (HLBF) before and after α1-adrenergic blockade [prazosin (50 μg/kg)], β-adrenergic blockade [propranolol (2 mg/kg)], and α1 + β-blockade. Hindlimb resistance was calculated as femoral arterial pressure/HLBF. During mild exercise, HLBF must be reduced below a threshold level before the reflex is activated. With initial reductions in HLBF, vasodilation occurred with the imposed ischemia. Once the muscle metaboreflex was elicited, hindlimb resistance increased. This increase in hindlimb resistance was abolished by α1-adrenergic blockade and exacerbated after β-adrenergic blockade. We conclude that metaboreflex activation during submaximal dynamic exercise causes sympathetically mediated α-adrenergic vasoconstriction in ischemic skeletal muscle. This limits the ability of the reflex to improve blood flow to the muscle. PMID:26475591

  15. Airway and Extracellular Matrix Mechanics in COPD

    PubMed Central

    Bidan, Cécile M.; Veldsink, Annemiek C.; Meurs, Herman; Gosens, Reinoud

    2015-01-01

    Chronic obstructive pulmonary disease (COPD) is one of the most common lung diseases worldwide, and is characterized by airflow obstruction that is not fully reversible with treatment. Even though airflow obstruction is caused by airway smooth muscle contraction, the extent of airway narrowing depends on a range of other structural and functional determinants that impact on active and passive tissue mechanics. Cells and extracellular matrix in the airway and parenchymal compartments respond both passively and actively to the mechanical stimulation induced by smooth muscle contraction. In this review, we summarize the factors that regulate airway narrowing and provide insight into the relative contributions of different constituents of the extracellular matrix and their biomechanical impact on airway obstruction. We then review the changes in extracellular matrix composition in the airway and parenchymal compartments at different stages of COPD, and finally discuss how these changes impact airway narrowing and the development of airway hyperresponsiveness. Finally, we position these data in the context of therapeutic research focused on defective tissue repair. As a conclusion, we propose that future works should primarily target mild or early COPD, prior to the widespread structural changes in the alveolar compartment that are more characteristic of severe COPD. PMID:26696894

  16. Vasoactive peptides upregulate mRNA expression and secretion of vascular endothelial growth factor in human airway smooth muscle cells.

    PubMed

    Alagappan, Vijay K T; Willems-Widyastuti, Anna; Seynhaeve, Ann L B; Garrelds, Ingrid M; ten Hagen, Timo L M; Saxena, Pramod R; Sharma, Hari S

    2007-01-01

    Airway remodeling and associated angiogenesis are documented features of asthma, of which the molecular mechanisms are not fully understood. Angiotensin (ANG)II and endothelin (ET)-1 are potent vasoconstricting circulatory hormones implicated in asthma. We investigated the effects of ANG II and ET-1 on human airway smooth muscle (ASM) cells proliferation and growth and examined the mRNA expression and release of the angiogenic peptide, vascular endothelial growth factor (VEGF). Serum deprived (48 h) human ASM cells were incubated with ANG II (100 nM) or ET-1 (10 nM) for 30 min, 1, 2, 4, 8, 16, and 24 h and the endogenous synthesis of VEGF was examined in relation to control cells receiving serum free culture medium. ET-1 induced time dependent DNA biosynthesis as determined by [3H]-thymidine incorporation assay. Using northern blot hybridization, we detected two mRNA species of 3.9 and 1.7 kb encoding VEGF in the cultured smooth muscle cells. Both ANG II and ET-1 induced the mRNA expression (two- to threefold) and secretion (1.8- to 2.8-fold) of VEGF reaching maximal levels between 4-8 h of incubation. Induced expression and release of VEGF declined after 8 h of ANG II incubation while levels remained elevated in the case of ET-1. The conditioned medium derived from ET-1-treated ASM cells induced [3H]-thymidine incorporation and cell number in porcine pulmonary artery endothelial as well as human umbilical vein endothelial cells. Moreover, the VEGF tyrosine kinase receptor inhibitor blocked the conditioned medium induced mitogenesis in endothelial cells. Our results suggest a potential role for ANG II and ET-1 in ASM cell growth and upregulation of VEGF that may participate in endothelial cell proliferation via paracrine mechanisms and thus causing pathological angiogenesis and vascular remodelling seen during asthma. PMID:17406064

  17. Targeting the urokinase plasminogen activator receptor enhances gene transfer to human airway epithelia

    PubMed Central

    Drapkin, Paola T.; O’Riordan, Catherine R.; Yi, Su Min; Chiorini, John A.; Cardella, Jonathan; Zabner, Joseph; Welsh, Michael J.

    2000-01-01

    Developing gene therapy for cystic fibrosis has been hindered by limited binding and endocytosis of vectors by human airway epithelia. Here we show that the apical membrane of airway epithelia express the urokinase plasminogen activator receptor (uPAR). Urokinase plasminogen activator (uPA), or a 7-residue peptide derived from this protein (u7-peptide), bound the receptor and stimulated apical endocytosis. Both ligands enhanced gene transfer by nonspecifically bound adenovirus and adeno-associated virus vectors and by a modified adenovirus vector that had been coupled to the u7-peptide. These data provide the first evidence that targeting an apical receptor can circumvent the two most important barriers to gene transfer in airway epithelia. Thus, the uPA/uPAR system may offer significant advantages for delivering genes and other pharmaceuticals to airway epithelia. PMID:10712430

  18. Targeting the urokinase plasminogen activator receptor enhances gene transfer to human airway epithelia.

    PubMed

    Drapkin, P T; O'Riordan, C R; Yi, S M; Chiorini, J A; Cardella, J; Zabner, J; Welsh, M J

    2000-03-01

    Developing gene therapy for cystic fibrosis has been hindered by limited binding and endocytosis of vectors by human airway epithelia. Here we show that the apical membrane of airway epithelia express the urokinase plasminogen activator receptor (uPAR). Urokinase plasminogen activator (uPA), or a 7-residue peptide derived from this protein (u7-peptide), bound the receptor and stimulated apical endocytosis. Both ligands enhanced gene transfer by nonspecifically bound adenovirus and adeno-associated virus vectors and by a modified adenovirus vector that had been coupled to the u7-peptide. These data provide the first evidence that targeting an apical receptor can circumvent the two most important barriers to gene transfer in airway epithelia. Thus, the uPA/uPAR system may offer significant advantages for delivering genes and other pharmaceuticals to airway epithelia. PMID:10712430

  19. Effects of age on muscarinic agonist-induced contraction an IP accumulation in airway smooth muscle

    SciTech Connect

    Wills-Karp, M. )

    1991-01-01

    The effects of age on carbachol-stimulated force development and ({sup 3}H)inositol phosphate production was studied in tracheal rings from guinea pigs aged 1 month and 25 months of age. The pD{sub 2} for the contractile response to carbachol was significantly reduced in tracheal tissues from old animals as compared to that of the young tissues, respectively. In contrast, inositol phosphate formation was not altered with increasing age when stimulated by carbachol or NaF, a direct activator of G proteins. Carbachol-induced inositol phosphate accumulation was inhibited by treatment with 1{mu}g/ml pertussis toxin, suggesting that IP1 accumulation is coupled to a pertussis-toxin-sensitive protein. The pD{sub 2} values for contraction were significantly different from the pD{sub 2} values for IP1 accumulation, in both young and old tissues, respectively. These data suggest that IP1 accumulation is not responsible for the decreased contractile ability in tracheal smooth muscle during aging.

  20. Does mental exertion alter maximal muscle activation?

    PubMed Central

    Rozand, Vianney; Pageaux, Benjamin; Marcora, Samuele M.; Papaxanthis, Charalambos; Lepers, Romuald

    2014-01-01

    Mental exertion is known to impair endurance performance, but its effects on neuromuscular function remain unclear. The purpose of this study was to test the hypothesis that mental exertion reduces torque and muscle activation during intermittent maximal voluntary contractions of the knee extensors. Ten subjects performed in a randomized order three separate mental exertion conditions lasting 27 min each: (i) high mental exertion (incongruent Stroop task), (ii) moderate mental exertion (congruent Stroop task), (iii) low mental exertion (watching a movie). In each condition, mental exertion was combined with 10 intermittent maximal voluntary contractions of the knee extensor muscles (one maximal voluntary contraction every 3 min). Neuromuscular function was assessed using electrical nerve stimulation. Maximal voluntary torque, maximal muscle activation and other neuromuscular parameters were similar across mental exertion conditions and did not change over time. These findings suggest that mental exertion does not affect neuromuscular function during intermittent maximal voluntary contractions of the knee extensors. PMID:25309404

  1. A Plasminogen Activator Inhibitor-1 Inhibitor Reduces Airway Remodeling in a Murine Model of Chronic Asthma

    PubMed Central

    Lee, Sun H.; Eren, Mesut; Vaughan, Douglas E.; Schleimer, Robert P.

    2012-01-01

    We previously reported that plasminogen activator inhibitor (PAI)-1 deficiency prevents collagen deposition in the airways of ovalbumin (OVA)-challenged mice. In this study, we explored the therapeutic utility of blocking PAI-1 in preventing airway remodeling, using a specific PAI-1 inhibitor, tiplaxtinin. C57BL/6J mice were immunized with intraperitoneal injections of OVA on Days 0, 3, and 6. Starting on Day 11, mice were challenged with phosphate-buffered saline or OVA by nebulization three times per week for 4 weeks. Tiplaxtinin was mixed with chow and administered orally from 1 day before the phosphate-buffered saline or OVA challenge. Lung tissues were harvested after challenge and characterized histologically for infiltrating inflammatory cells, mucus-secreting goblet cells, and collagen deposition. Airway hyperresponsiveness was measured using whole-body plethysmography. Tiplaxtinin treatment significantly decreased levels of PAI-1 activity in bronchoalveolar lavage fluids, which indicates successful blockage of PAI-1 activity in the airways. The number of infiltrated inflammatory cells was reduced by tiplaxtinin treatment in the lungs of the OVA-challenged mice. Furthermore, oral administration of tiplaxtinin significantly attenuated the degree of goblet cell hyperplasia and collagen deposition in the airways of the OVA-challenged mice, and methacholine-induced airway hyperresponsiveness was effectively reduced by tiplaxtinin in these animals. This study supports our previous findings that PAI-1 promotes airway remodeling in a murine model of chronic asthma, and suggests that PAI-1 may be a novel target of treatment of airway remodeling in asthma. PMID:22323366

  2. A plasminogen activator inhibitor-1 inhibitor reduces airway remodeling in a murine model of chronic asthma.

    PubMed

    Lee, Sun H; Eren, Mesut; Vaughan, Douglas E; Schleimer, Robert P; Cho, Seong H

    2012-06-01

    We previously reported that plasminogen activator inhibitor (PAI)-1 deficiency prevents collagen deposition in the airways of ovalbumin (OVA)-challenged mice. In this study, we explored the therapeutic utility of blocking PAI-1 in preventing airway remodeling, using a specific PAI-1 inhibitor, tiplaxtinin. C57BL/6J mice were immunized with intraperitoneal injections of OVA on Days 0, 3, and 6. Starting on Day 11, mice were challenged with phosphate-buffered saline or OVA by nebulization three times per week for 4 weeks. Tiplaxtinin was mixed with chow and administered orally from 1 day before the phosphate-buffered saline or OVA challenge. Lung tissues were harvested after challenge and characterized histologically for infiltrating inflammatory cells, mucus-secreting goblet cells, and collagen deposition. Airway hyperresponsiveness was measured using whole-body plethysmography. Tiplaxtinin treatment significantly decreased levels of PAI-1 activity in bronchoalveolar lavage fluids, which indicates successful blockage of PAI-1 activity in the airways. The number of infiltrated inflammatory cells was reduced by tiplaxtinin treatment in the lungs of the OVA-challenged mice. Furthermore, oral administration of tiplaxtinin significantly attenuated the degree of goblet cell hyperplasia and collagen deposition in the airways of the OVA-challenged mice, and methacholine-induced airway hyperresponsiveness was effectively reduced by tiplaxtinin in these animals. This study supports our previous findings that PAI-1 promotes airway remodeling in a murine model of chronic asthma, and suggests that PAI-1 may be a novel target of treatment of airway remodeling in asthma. PMID:22323366

  3. Selective Activation of the Infraspinatus Muscle

    PubMed Central

    Ha, Sung-Min; Kwon, Oh-Yun; Cynn, Heon-Seock; Lee, Won-Hwee; Kim, Su-Jung; Park, Kyue-Nam

    2013-01-01

    Context: To improve selective infraspinatus muscle strength and endurance, researchers have recommended selective shoulder external-rotation exercise during rehabilitation or athletic conditioning programs. Although selective strengthening of the infraspinatus muscle is recommended for therapy and training, limited information is available to help clinicians design a selective strengthening program. Objective: To determine the most effective of 4 shoulder external-rotation exercises for selectively stimulating infraspinatus muscle activity while minimizing the use of the middle trapezius and posterior deltoid muscles. Design: Cross-sectional study. Setting: University research laboratory. Patients or Other Participants: A total of 30 healthy participants (24 men, 6 women; age = 22.6 ± 1.7 years, height = 176.2 ± 4.5 cm, mass = 65.6 ± 7.4 kg) from a university population. Intervention(s): The participants were instructed to perform 4 exercises: (1) prone horizontal abduction with external rotation (PER), (2) side-lying wiper exercise (SWE), (3) side-lying external rotation (SER), and (4) standing external-rotation exercise (STER). Main Outcome Measure(s): Surface electromyography signals were recorded from the infraspinatus, middle trapezius, and posterior deltoid muscles. Differences among the exercise positions were tested using a 1-way repeated-measures analysis of variance with Bonferroni adjustment. Results: The infraspinatus muscle activity was greater in the SWE (55.98% ± 18.79%) than in the PER (46.14% ± 15.65%), SER (43.38% ± 22.26%), and STER (26.11% ± 15.00%) (F3,87 = 19.97, P < .001). Furthermore, the SWE elicited the least amount of activity in the middle trapezius muscle (F3,87 = 20.15, P < .001). Posterior deltoid muscle activity was similar in the SWE and SER but less than that measured in the PER and STER (F3,87 = 25.10, P < .001). Conclusions: The SWE was superior to the PER, SER, and STER in maximizing infraspinatus activity with the least

  4. Kalanchoe pinnata inhibits mast cell activation and prevents allergic airway disease.

    PubMed

    Cruz, E A; Reuter, S; Martin, H; Dehzad, N; Muzitano, M F; Costa, S S; Rossi-Bergmann, B; Buhl, R; Stassen, M; Taube, C

    2012-01-15

    Aqueous extract of Kalanchoe pinnata (Kp) have been found effective in models to reduce acute anaphylactic reactions. In the present study, we investigate the effect of Kp and the flavonoid quercetin (QE) and quercitrin (QI) on mast cell activation in vitro and in a model of allergic airway disease in vivo. Treatment with Kp and QE in vitro inhibited degranulation and cytokine production of bone marrow-derived mast cells following IgE/FcɛRI crosslinking, whereas treatment with QI had no effect. Similarly, in vivo treatment with Kp and QE decreased development of airway hyperresponsiveness, airway inflammation, goblet cell metaplasia and production of IL-5, IL-13 and TNF. In contrast, treatment with QI had no effect on these parameters. These findings demonstrate that treatment with Kp or QE is effective in treatment of allergic airway disease, providing new insights to the immunomodulatory functions of this plant. PMID:21802918

  5. Length adaptation of smooth muscle contractile filaments in response to sustained activation.

    PubMed

    Stålhand, Jonas; Holzapfel, Gerhard A

    2016-05-21

    Airway and bladder smooth muscles are known to undergo length adaptation under sustained contraction. This adaptation process entails a remodelling of the intracellular actin and myosin filaments which shifts the peak of the active force-length curve towards the current length. Smooth muscles are therefore able to generate the maximum force over a wide range of lengths. In contrast, length adaptation of vascular smooth muscle has attracted very little attention and only a handful of studies have been reported. Although their results are conflicting on the existence of a length adaptation process in vascular smooth muscle, it seems that, at least, peripheral arteries and arterioles undergo such adaptation. This is of interest since peripheral vessels are responsible for pressure regulation, and a length adaptation will affect the function of the cardiovascular system. It has, e.g., been suggested that the inward remodelling of resistance vessels associated with hypertension disorders may be related to smooth muscle adaptation. In this study we develop a continuum mechanical model for vascular smooth muscle length adaptation by assuming that the muscle cells remodel the actomyosin network such that the peak of the active stress-stretch curve is shifted towards the operating point. The model is specialised to hamster cheek pouch arterioles and the simulated response to stepwise length changes under contraction. The results show that the model is able to recover the salient features of length adaptation reported in the literature. PMID:26925813

  6. Bronchoconstriction and airway biology: potential impact and therapeutic opportunities.

    PubMed

    Gosens, Reinoud; Grainge, Chris

    2015-03-01

    Recent work has demonstrated that mechanical forces occurring in the airway as a consequence of bronchoconstriction are sufficient to not only induce symptoms but also influence airway biology. Animal and human in vitro and in vivo work demonstrates that the airways are structurally and functionally altered by mechanical stress induced by bronchoconstriction. Compression of the airway epithelium and mechanosensing by the airway smooth muscle trigger the activation and release of growth factors, causing cell proliferation, extracellular matrix protein accumulation, and goblet cell differentiation. These effects of bronchoconstriction are of major importance to asthma pathophysiology and appear sufficient to induce remodeling independent of the inflammatory response. We review these findings in detail and discuss previous studies in light of this new evidence regarding the influence of mechanical forces in the airways. Furthermore, we highlight potential impacts of therapies influencing mechanical forces on airway structure and function in asthma. PMID:25732446

  7. Smooth muscle cell calcium activation mechanisms

    PubMed Central

    Berridge, Michael J

    2008-01-01

    Smooth muscle cell (SMC) contraction is controlled by the Ca2+ and Rho kinase signalling pathways. While the SMC Rho kinase system seems to be reasonably constant, there is enormous variation with regard to the mechanisms responsible for generating Ca2+ signals. One way of dealing with this diversity is to consider how this system has been adapted to control different SMC functions. Phasic SMCs (vas deferens, uterus and bladder) rely on membrane depolarization to drive Ca2+ influx across the plasma membrane. This depolarization can be induced by neurotransmitters or through the operation of a membrane oscillator. Many tonic SMCs (vascular, airway and corpus cavernosum) are driven by a cytosolic Ca2+ oscillator that generates periodic pulses of Ca2+. A similar oscillator is present in pacemaker cells such as the interstitial cells of Cajal (ICCs) and atypical SMCs that control other tonic SMCs (gastrointestinal, urethra, ureter). The changes in membrane potential induced by these cytosolic oscillators does not drive contraction directly but it functions to couple together individual oscillators to provide the synchronization that is a characteristic feature of many tonic SMCs. PMID:18787034

  8. Muscle activation during various hamstring exercises.

    PubMed

    McAllister, Matt J; Hammond, Kelley G; Schilling, Brian K; Ferreria, Lucas C; Reed, Jacob P; Weiss, Lawrence W

    2014-06-01

    The dorsal muscles of the lower torso and extremities have often been denoted the "posterior chain." These muscles are used to support the thoracic and lumbar spine and peripheral joints, including the hip, knee, and ankle on the dorsal aspect of the body. This study investigated the relative muscle activity of the hamstring group and selected surrounding musculature during the leg curl, good morning, glute-ham raise, and Romanian deadlift (RDL). Twelve healthy, weight-trained men performed duplicate trials of single repetitions at 85% 1-repetition maximum for each lift in random order, during which surface electromyography and joint angle data were obtained. Repeated measures analysis of variance across the 4 exercises was performed to compare the activity from the erector spinae (ES), gluteus medius (GMed), semitendinosus (ST), biceps femoris (BF), and medial gastrocnemius (MGas). Significant differences (p ≤ 0.05) were noted in eccentric muscle activity between exercise for the MGas (p < 0.027), ST (p < 0.001), BF (p < 0.001), and ES (p = 0.032), and in concentric muscle activity, for the ES (p < 0.001), BF (p = 0.010), ST (p = 0.009), MGas (p < 0.001), and the GMed (p = 0.018). Bonferroni post hoc analysis revealed significant pairwise differences during eccentric actions for the BF, ST, and MGas. Post hoc analysis also revealed significant pairwise differences during concentric actions for the ES, BF, ST, MGas, and GMed. Each of these showed effect sizes that are large or greater. The main findings of this investigation are that the ST is substantially more active than the BF among all exercises, and hamstring activity was maximized in the RDL and glute-ham raise. Therefore, athletes and coaches who seek to maximize the involvement of the hamstring musculature should consider focusing on the glute-ham raise and RDL. PMID:24149748

  9. Regulation of airway neurogenic inflammation by neutral endopeptidase.

    PubMed

    Di Maria, G U; Bellofiore, S; Geppetti, P

    1998-12-01

    Airway neurogenic inflammation is caused by tachykinins released from peripheral nerve endings of sensory neurons within the airways, and is characterized by plasma protein extravasation, airway smooth muscle contraction and increased secretion of mucus. Tachykinins are degraded and inactivated by neutral endopeptidase (NEP), a membrane-bound metallopeptidase, which is located mainly at the surface of airway epithelial cells, but is also present in airway smooth muscle cells, submucosal gland cells and fibroblasts. The key role of NEP in limiting and regulating the neurogenic inflammation provoked by different stimuli has been demonstrated in a large series of studies published in recent years. It has also been shown that a variety of factors, which are relevant for airway diseases, including viral infections, allergen exposure, inhalation of cigarette smoke and other respiratory irritants, is able to reduce NEP activity, thus enhancing the effects of tachykinins within the airways. On the basis of these observations, the reduction of neutral endopeptidase activity may be regarded as a factor that switches neurogenic airway responses from their physiological and protective functions to a detrimental role that increases and perpetuates airway inflammation. However, further studies are needed to assess the role of neutral endopeptidase down regulation in the pathogenesis of asthma and other inflammatory airway diseases. PMID:9877509

  10. Comparative Sensitivity Analysis of Muscle Activation Dynamics

    PubMed Central

    Rockenfeller, Robert; Günther, Michael; Schmitt, Syn; Götz, Thomas

    2015-01-01

    We mathematically compared two models of mammalian striated muscle activation dynamics proposed by Hatze and Zajac. Both models are representative for a broad variety of biomechanical models formulated as ordinary differential equations (ODEs). These models incorporate parameters that directly represent known physiological properties. Other parameters have been introduced to reproduce empirical observations. We used sensitivity analysis to investigate the influence of model parameters on the ODE solutions. In addition, we expanded an existing approach to treating initial conditions as parameters and to calculating second-order sensitivities. Furthermore, we used a global sensitivity analysis approach to include finite ranges of parameter values. Hence, a theoretician striving for model reduction could use the method for identifying particularly low sensitivities to detect superfluous parameters. An experimenter could use it for identifying particularly high sensitivities to improve parameter estimation. Hatze's nonlinear model incorporates some parameters to which activation dynamics is clearly more sensitive than to any parameter in Zajac's linear model. Other than Zajac's model, Hatze's model can, however, reproduce measured shifts in optimal muscle length with varied muscle activity. Accordingly we extracted a specific parameter set for Hatze's model that combines best with a particular muscle force-length relation. PMID:26417379

  11. Comparative Sensitivity Analysis of Muscle Activation Dynamics.

    PubMed

    Rockenfeller, Robert; Günther, Michael; Schmitt, Syn; Götz, Thomas

    2015-01-01

    We mathematically compared two models of mammalian striated muscle activation dynamics proposed by Hatze and Zajac. Both models are representative for a broad variety of biomechanical models formulated as ordinary differential equations (ODEs). These models incorporate parameters that directly represent known physiological properties. Other parameters have been introduced to reproduce empirical observations. We used sensitivity analysis to investigate the influence of model parameters on the ODE solutions. In addition, we expanded an existing approach to treating initial conditions as parameters and to calculating second-order sensitivities. Furthermore, we used a global sensitivity analysis approach to include finite ranges of parameter values. Hence, a theoretician striving for model reduction could use the method for identifying particularly low sensitivities to detect superfluous parameters. An experimenter could use it for identifying particularly high sensitivities to improve parameter estimation. Hatze's nonlinear model incorporates some parameters to which activation dynamics is clearly more sensitive than to any parameter in Zajac's linear model. Other than Zajac's model, Hatze's model can, however, reproduce measured shifts in optimal muscle length with varied muscle activity. Accordingly we extracted a specific parameter set for Hatze's model that combines best with a particular muscle force-length relation. PMID:26417379

  12. Alternaria extract activates autophagy that induces IL-18 release from airway epithelial cells.

    PubMed

    Murai, Hiroki; Okazaki, Shintaro; Hayashi, Hisako; Kawakita, Akiko; Hosoki, Koa; Yasutomi, Motoko; Sur, Sanjiv; Ohshima, Yusei

    2015-09-01

    Alternaria alternata is a major outdoor allergen that causes allergic airway diseases. Alternaria extract (ALT-E) has been shown to induce airway epithelial cells to release IL-18 and thereby initiate Th2-type responses. We investigated the underlying mechanisms involved in IL-18 release from ALT-E-stimulated airway epithelial cells. Normal human bronchial epithelial cells and A549 human lung adenocarcinoma cells were stimulated with ALT-E in the presence of different inhibitors of autophagy or caspases. IL-18 levels in culture supernatants were measured by ELISA. The numbers of autophagosomes, an LC3-I to LC3-II conversion, and p62 degradation were determined by immunofluorescence staining and immunoblotting. 3-methyladenine and bafilomycin, which inhibit the formation of preautophagosomal structures and autolysosomes, respectively, suppressed ALT-E-induced IL-18 release by cells, whereas caspase 1 and 8 inhibitors did not. ALT-E-stimulation increased autophagosome formation, LC-3 conversion, and p62 degradation in airway epithelial cells. LPS-stimulation induced the LC3 conversion in A549 cells, but did not induce IL-18 release or p62 degradation. Unlike LPS, ALT-E induced airway epithelial cells to release IL-18 via an autophagy dependent, caspase 1 and 8 independent pathway. Although autophagy has been shown to negatively regulate canonical inflammasome activity in TLR-stimulated macrophages, our data indicates that this process is an unconventional mechanism of IL-18 secretion by airway epithelial cells. PMID:26032499

  13. L-thyroxine promotes a proliferative airway smooth muscle phenotype in the presence of TGF-β1.

    PubMed

    Dekkers, Bart G J; Naeimi, Saeideh; Bos, I Sophie T; Menzen, Mark H; Halayko, Andrew J; Hashjin, Goudarz Sadeghi; Meurs, Herman

    2015-02-01

    Hypothyroidism may reduce, whereas hyperthyroidism may aggravate, asthma symptoms. The mechanisms underlying this relationship are largely unknown. Since thyroid hormones have central roles in cell growth and differentiation, we hypothesized that airway remodeling, in particular increased airway smooth muscle (ASM) mass, may be involved. To address this hypothesis, we investigated the effects of triiodothyronine (T3) and l-thyroxine (T4) in the absence and presence of the profibrotic transforming growth factor (TGF)-β1 on human ASM cell phenotype switching. T3 (1-100 nM) and T4 (1-100 nM) did not affect basal ASM proliferation. However, when combined with TGF-β1 (2 ng/ml), T4 synergistically increased the proliferative response, whereas only a minor effect was observed for T3. In line with a switch from a contractile to a proliferative ASM phenotype, T4 reduced the TGF-β1-induced contractile protein expression by ∼50%. Cotreatment with T3 reduced TGF-β1-induced contractile protein expression by ∼25%. The synergistic increase in proliferation was almost fully inhibited by the integrin αvβ3 antagonist tetrac (100 nM), whereas no significant effects of the thyroid receptor antagonist 1-850 (3 μM) were observed. Inhibition of MEK1/2, downstream of the integrin αvβ3, also inhibited the T4- and TGF-β1-induced proliferative responses. Collectively, the results indicate that T4, and to a lesser extent T3, promotes a proliferative ASM phenotype in the presence of TGF-β1, which is predominantly mediated by the membrane-bound T4 receptor αvβ3. These results indicate that thyroid hormones may enhance ASM remodeling in asthma, which could be of relevance for hyperthyroid patients with this disease. PMID:25480330

  14. BET Bromodomains Regulate Transforming Growth Factor-β-induced Proliferation and Cytokine Release in Asthmatic Airway Smooth Muscle*

    PubMed Central

    Perry, Mark M.; Durham, Andrew L.; Austin, Philip J.; Adcock, Ian M.; Chung, Kian Fan

    2015-01-01

    Airway smooth muscle (ASM) mass is increased in asthma, and ASM cells from patients with asthma are hyperproliferative and release more IL-6 and CXCL8. The BET (bromo- and extra-terminal) family of proteins (Brd2, Brd3, and Brd4) govern the assembly of histone acetylation-dependent chromatin complexes. We have examined whether they modulate proliferation and cytokine expression in asthmatic ASM cells by studying the effect of BET bromodomain mimics JQ1/SGCBD01 and I-BET762. ASM cells from healthy individuals and nonsevere and severe asthmatics were pretreated with JQ1/SGCBD01 and I-BET762 prior to stimulation with FCS and TGF-β. Proliferation was measured by BrdU incorporation. IL-6 and CXCL8 release was measured by ELISA, and mRNA expression was measured by quantitative RT-PCR. ChIP using a specific anti-Brd4 antibody and PCR primers directed against the transcriptional start site of IL-6 and CXCL8 gene promoters was performed. Neither JQ1/SGCBD01 nor I-BET762 had any effect on ASM cell viability. JQ1/SGCBD01 and I-BET762 inhibited FCS+TGF-β-induced ASM cell proliferation and IL-6 and CXCL8 release in healthy individuals (≥ 30 nm) and in nonsevere and severe asthma patients (≥100 nm), with the latter requiring higher concentrations of these mimics. JQ1/SGCBD01 reduced Brd4 binding to IL8 and IL6 promoters induced by FCS+TGF-β. Mimics of BET bromodomains inhibit aberrant ASM cell proliferation and inflammation with lesser efficiency in those from asthmatic patients. They may be effective in reducing airway remodeling in asthma. PMID:25697361

  15. A new nitrosyl ruthenium complex nitric oxide donor presents higher efficacy than sodium nitroprusside on relaxation of airway smooth muscle.

    PubMed

    Castro, Patrícia F S; Pereira, Amanda de C; Rogrigues, Gerson J; Batista, Aline C; da Silva, Roberto S; Bendhack, Lusiane M; Rocha, Matheus L

    2011-08-17

    Nitric oxide (NO) has been demonstrated to be the primary agent in relaxing airways in humans and animals. We investigated the mechanisms involved in the relaxation induced by NO-donors, ruthenium complex [Ru(terpy)(bdq)NO(+)](3+) (TERPY) and sodium nitroprusside (SNP) in isolated trachea of rats contracted with carbachol in an isolated organs chamber. For instance, we verified the contribution of K(+) channels, the importance of sGC/cGMP pathway, the influence of the extra and intracellular Ca(2+) sources and the contribution of the epithelium on the relaxing response. Additionally, we have used confocal microscopy in order to analyze the action of the NO-donors on cytosolic Ca(2+) concentration. The results demonstrated that both compounds led to the relaxation of trachea in a dependent-concentration way. However, the maximum effect (E(max)) of TERPY is higher than the SNP. The relaxation induced by SNP (but not TERPY) was significantly reduced by pretreatment with ODQ (sGC inhibitor). Only TERPY-induced relaxation was reduced by tetraethylammonium (K(+) channels blocker) and by pre-contraction with 75mM KCl (membrane depolarization). The response to both NO-donors was not altered by the presence of thapsigargin (sarcoplasmic reticulum Ca(2+)-ATPase inhibitor). The epithelium removal has reduced the relaxation only to SNP, and it has no effect on TERPY. The both NO-donors reduced the contraction evoked by Ca(2+) influx, while TERPY have shown a higher inhibitory effect on contraction. Moreover, the TERPY was more effective than SNP in reducing the cytosolic Ca(2+) concentration measured by confocal microscopy. In conclusion, these results show that TERPY induces airway smooth muscle relaxation by cGMP-independent mechanisms, it involves the fluxes of Ca(2+) and K(+) across the membrane, it is more effective in reducing cytosolic Ca(2+) concentration and inducing relaxation in the rat trachea than the standard drug, SNP. PMID:21605670

  16. The Role of Inflammation Resolution Speed in Airway Smooth Muscle Mass Accumulation in Asthma: Insight from a Theoretical Model

    PubMed Central

    Chernyavsky, Igor L.; Croisier, Huguette; Chapman, Lloyd A. C.; Kimpton, Laura S.; Hiorns, Jonathan E.; Brook, Bindi S.; Jensen, Oliver E.; Billington, Charlotte K.; Hall, Ian P.; Johnson, Simon R.

    2014-01-01

    Despite a large amount of in vitro data, the dynamics of airway smooth muscle (ASM) mass increase in the airways of patients with asthma is not well understood. Here, we present a novel mathematical model that describes qualitatively the growth dynamics of ASM cells over short and long terms in the normal and inflammatory environments typically observed in asthma. The degree of ASM accumulation can be explained by an increase in the rate at which ASM cells switch between non-proliferative and proliferative states, driven by episodic inflammatory events. Our model explores the idea that remodelling due to ASM hyperplasia increases with the frequency and magnitude of these inflammatory events, relative to certain sensitivity thresholds. It highlights the importance of inflammation resolution speed by showing that when resolution is slow, even a series of small exacerbation events can result in significant remodelling, which persists after the inflammatory episodes. In addition, we demonstrate how the uncertainty in long-term outcome may be quantified and used to design an optimal low-risk individual anti-proliferative treatment strategy. The model shows that the rate of clearance of ASM proliferation and recruitment factors after an acute inflammatory event is a potentially important, and hitherto unrecognised, target for anti-remodelling therapy in asthma. It also suggests new ways of quantifying inflammation severity that could improve prediction of the extent of ASM accumulation. This ASM growth model should prove useful for designing new experiments or as a building block of more detailed multi-cellular tissue-level models. PMID:24632688

  17. ΔF508 CFTR processing correction and activity in polarized airway and non-airway cell monolayers

    PubMed Central

    Rowe, SM; Pyle, LC; Jurkevante, A; Varga, K; Collawn, J; Sloane, PA; Woodworth, B; Mazur, M; Fulton, J; Fan, L; Li, Y; Fortenberry, J; Sorscher, EJ; Clancy, JP

    2010-01-01

    We examined the activity of ΔF508 cystic fibrosis transmembrane conductance regulator (CFTR) stably expressed in polarized cystic fibrosis bronchial epithelial cells (CFBE41o−) human airway cells and Fisher Rat Thyroid (FRT) cells following treatment with low temperature and a panel of small molecule correctors of ΔF508 CFTR misprocessing. Corr-4a increased ΔF508 CFTR-dependent Cl− conductance in both cell types, whereas treatment with VRT-325 or VRT-640 increased activity only in FRT cells. Total currents stimulated by forskolin and genistein demonstrated similar dose/response effects to Corr-4a treatment in each cell type. When examining the relative contribution of forskolin and genistein to total stimulated current, CFBE41o− cells had smaller forskolin-stimulated Isc following either low temperature or corr-4a treatment (10–30% of the total Isc produced by the combination of both CFTR agonists). In contrast, forskolin consistently contributed greater than 40% of total Isc in ΔF508 CFTR expressing FRT cells corrected with low temperature, and corr-4a treatment preferentially enhanced forskolin dependent currents only in FRT cells (60% of total Isc). ΔF508 CFTR cDNA transcript levels, ΔF508 CFTR C band levels, or cAMP signaling did not account for the reduced forskolin response in CFBE41o− cells. Treatment with non-specific inhibitors of phosphodiesterases (papaverine) or phosphatases (endothall) did not restore ΔF508 CFTR activation by forskolin in CFBE41o− cells, indicating that the Cl− transport defect in airway cells is distal to cAMP or its metabolism. The results identify important differences in ΔF508 CFTR activation in polarizing epithelial models of CF, and have important implications regarding detection of rescued of ΔF508 CFTR in vivo. PMID:20226262

  18. The proprioceptive reflex control of the intercostal muscles during their voluntary activation

    PubMed Central

    Davis, J. Newsom; Sears, T. A.

    1970-01-01

    1. A quantitative study has been made of the reflex effects of sudden changes in mechanical load on contracting human intercostal muscles during willed breathing movements involving the chest wall. Averaging techniques were applied to recordings of electromyogram (EMG) and lung volume, and to other parameters of breathing. 2. Load changes were effected for brief periods (10-150 msec) at any predetermined lung volume by sudden connexion of the airway to a pressure source variable between ± 80 cm H2O so that respiratory movement could be either assisted or opposed. In some experiments airway resistance was suddenly reduced by porting from a high to a low resistance external airway. 3. Contracting inspiratory and expiratory intercostal muscles showed a `silent period' with unloading which is attributed to the sudden withdrawal from intercostal motoneurones of monosynaptic excitation of muscle spindle origin. 4. For both inspiratory and expiratory intercostal muscles the typical immediate effect of an increase in load was an inhibitory response (IR) with a latency of about 22 msec followed by an excitatory response (ER) with a latency of 50-60 msec. 5. It was established using brief duration stimuli (< 40 msec) that the IR depended on mechanical events associated with the onset of stimulation, whereas stimuli greater than 40 msec in duration were required to evoke the ER. 6. For constant expiratory flow rate and a constant load, the ER of expiratory intercostal muscles increased as lung volume decreased within the limits set by maximal activation of the motoneurone pool as residual volume was approached. 7. The ER to a constant load increased directly with the expiratory flow rate at which the load applied, also within limits set by maximal activation of the motoneurone pool. 8. For a given load, the ER during phonation was greater than that occurring at a similar expiratory flow rate without phonation when the resistance of the phonating larynx was mimicked by an

  19. Patterns of muscle activity for digital coarticulation

    PubMed Central

    Winges, Sara A.; Furuya, Shinichi; Faber, Nathaniel J.

    2013-01-01

    Although piano playing is a highly skilled task, basic features of motor pattern generation may be shared across tasks involving fine movements, such as handling coins, fingering food, or using a touch screen. The scripted and sequential nature of piano playing offered the opportunity to quantify the neuromuscular basis of coarticulation, i.e., the manner in which the muscle activation for one sequential element is altered to facilitate production of the preceding and subsequent elements. Ten pianists were asked to play selected pieces with the right hand at a uniform tempo. Key-press times were recorded along with the electromyographic (EMG) activity from seven channels: thumb flexor and abductor muscles, a flexor for each finger, and the four-finger extensor muscle. For the thumb and index finger, principal components of EMG waveforms revealed highly consistent variations in the shape of the flexor bursts, depending on the type of sequence in which a particular central key press was embedded. For all digits, the duration of the central EMG burst scaled, along with slight variations across subjects in the duration of the interkeystroke intervals. Even within a narrow time frame (about 100 ms) centered on the central EMG burst, the exact balance of EMG amplitudes across multiple muscles depended on the nature of the preceding and subsequent key presses. This fails to support the idea of fixed burst patterns executed in sequential phases and instead provides evidence for neuromuscular coarticulation throughout the time course of a hand movement sequence. PMID:23596338

  20. Comparative Study of Protective Effects of Salbutamol and Beclomethasone against Insulin Induced Airway Hyper-reactivity on Isolated Tracheal Smooth Muscle of Guinea Pig

    PubMed Central

    Sharif, Mahjabeen; Tayyaba Khan, Bushra; Bakhtiar, Salman; Anwar, Mohammad Asim

    2015-01-01

    Inhalational insulin was withdrawn from the market due to its potential to produce airway hyper-reactivity and bronchoconstriction. So the present study was designed to explore the acute effects of insulin on airway reactivity of guinea pigs and protective effects of salbutamol and beclomethasone against insulin induced airway hyper-responsiveness on isolated tracheal smooth muscle of guinea pig. Effects of varying concentrations of insulin (10-7 to 10-3 M), insulin pretreated with fixed concentration of salbutamol (10-7 M) and beclomethasone (10-6 M) were studied on isolated tracheal tissue of guinea pig by constructing cumulative concentration response curves. Changes in tracheal smooth muscle contractions were recorded on four channel oscillograph. The mean ± SEM of maximum amplitudes of contraction with increasing concentrations of insulin, insulin pretreated with fixed concentration of salbutamol and beclomethasone were 35 ± 1.13 mm, 14.55 ± 0.62 mm and 22 ± 1.154 mm respectively. Although salbutamol and beclomethasone both had a profound inhibitory effect on insulin induced airway hyper-reactivity, yet salbutamol is more efficacious than beclomethasone. So we suggest that pretreatment of inhaled insulin with salbutamol may be preferred over beclomethasone in amelioration of its potential respiratory adverse effects such as bronchoconstriction. PMID:25901165

  1. Mimicking muscle activity with electrical stimulation

    NASA Astrophysics Data System (ADS)

    Johnson, Lise A.; Fuglevand, Andrew J.

    2011-02-01

    Functional electrical stimulation is a rehabilitation technology that can restore some degree of motor function in individuals who have sustained a spinal cord injury or stroke. One way to identify the spatio-temporal patterns of muscle stimulation needed to elicit complex upper limb movements is to use electromyographic (EMG) activity recorded from able-bodied subjects as a template for electrical stimulation. However, this requires a transfer function to convert the recorded (or predicted) EMG signals into an appropriate pattern of electrical stimulation. Here we develop a generalized transfer function that maps EMG activity into a stimulation pattern that modulates muscle output by varying both the pulse frequency and the pulse amplitude. We show that the stimulation patterns produced by this transfer function mimic the active state measured by EMG insofar as they reproduce with good fidelity the complex patterns of joint torque and joint displacement.

  2. Pim1 kinase activity preserves airway epithelial integrity upon house dust mite exposure.

    PubMed

    de Vries, M; Hesse, L; Jonker, M R; van den Berge, M; van Oosterhout, A J M; Heijink, I H; Nawijn, M C

    2015-12-01

    Most patients with allergic asthma are sensitized to house dust mite (HDM). The allergenicity of HDM largely depends on disruption of the integrity and proinflammatory activation of the airway epithelium. In this study, we hypothesized that Pim1 kinase activity attenuates HDM-induced asthma by preserving airway epithelial integrity. The effects of Pim1 kinase activity on barrier function and release of the proinflammatory mediators IL-1α and CCL20 were studied in vitro in 16HBE and primary bronchial epithelial cells (PBECs). Pim1-proficient and -deficient mice were exposed to a HDM-driven model of allergic asthma, and airway hyperresponsiveness (AHR) was measured upon methacholine challenge. Airway inflammation and proinflammatory mediators in lung tissue and BAL fluid were determined. We observed that inhibition of Pim1 kinase prolongs the HDM-induced loss of barrier function in 16HBE cells and sensitizes PBECs to HDM-induced barrier dysfunction. Additionally, inhibition of Pim1 kinase increased the HDM-induced proinflammatory activity of 16HBE cells as measured by IL-1α secretion. In line herewith, HDM exposure induced an enhanced production of the proinflammatory chemokines CCL17 and CCL20 in Pim1-deficient mice compared with wild-type controls. While we observed a marked increase in eosinophilic and neutrophilic granulocytes as well as mucus cell metaplasia and AHR to methacholine in mice exposed to HDM, these parameters were independent of Pim1 kinase activity. In contrast, levels of the Th2-cytokines IL-5 and IL-10 were significantly augmented in HDM-treated Pim1-deficient mice. Taken together, our study shows that Pim1 kinase activity maintains airway epithelial integrity and protects against HDM-induced proinflammatory activation of the airway epithelium. PMID:26453516

  3. Airway Tissue Plasminogen Activator Prevents Acute Mortality Due to Lethal Sulfur Mustard Inhalation

    PubMed Central

    Veress, Livia A.; Anderson, Dana R.; Hendry-Hofer, Tara B.; Houin, Paul R.; Rioux, Jacqueline S.; Garlick, Rhonda B.; Loader, Joan E.; Paradiso, Danielle C.; Smith, Russell W.; Rancourt, Raymond C.; Holmes, Wesley W.; White, Carl W.

    2015-01-01

    Rationale: Sulfur mustard (SM) is a chemical weapon stockpiled today in volatile regions of the world. SM inhalation causes a life-threatening airway injury characterized by airway obstruction from fibrin casts, which can lead to respiratory failure and death. Mortality in those requiring intubation is more than 80%. No therapy exists to prevent mortality after SM exposure. Our previous work using the less toxic analog of SM, 2-chloroethyl ethyl sulfide, identified tissue plasminogen activator (tPA) an effective rescue therapy for airway cast obstruction (Veress, L. A., Hendry-Hofer, T. B., Loader, J. E., Rioux, J. S., Garlick, R. B., and White, C. W. (2013). Tissue plasminogen activator prevents mortality from sulfur mustard analog-induced airway obstruction. Am. J. Respir. Cell Mol. Biol. 48, 439–447). It is not known if exposure to neat SM vapor, the primary agent used in chemical warfare, will also cause death due to airway casts, and if tPA could be used to improve outcome. Methods: Adult rats were exposed to SM, and when oxygen saturation reached less than 85% (median: 6.5 h), intratracheal tPA or placebo was given under isoflurane anesthesia every 4 h for 48 h. Oxygen saturation, clinical distress, and arterial blood gases were assessed. Microdissection was done to assess airway obstruction by casts. Results: Intratracheal tPA treatment eliminated mortality (0% at 48 h) and greatly improved morbidity after lethal SM inhalation (100% death in controls). tPA normalized SM-associated hypoxemia, hypercarbia, and lactic acidosis, and improved respiratory distress. Moreover, tPA treatment resulted in greatly diminished airway casts, preventing respiratory failure from airway obstruction. Conclusions: tPA given via airway more than 6 h after exposure prevented death from lethal SM inhalation, and normalized oxygenation and ventilation defects, thereby rescuing from respiratory distress and failure. Intra-airway tPA should be considered as a life

  4. The active contribution of Toll-like receptors to allergic airway inflammation.

    PubMed

    Chen, Keqiang; Xiang, Yi; Yao, Xiaohong; Liu, Ying; Gong, Wanghua; Yoshimura, Teizo; Wang, Ji Ming

    2011-10-01

    Epithelia lining the respiratory tract represent a major portal of entry for microorganisms and allergens and are equipped with innate and adaptive immune signaling receptors for host protection. These include Toll-like receptors (TLRs) that recognize microbial components and evoke diverse responses in cells of the respiratory system. TLR stimulation by microorganism-derived molecules activates antigen presenting cells, control T helper (Th) 1, Th2, and Th17 immune cell differentiation, cytokine production by mast cells, and activation of eosinophils. It is clear that TLR are involved in the pathophysiology of allergic airway diseases such as asthma. Dendritic cells (DCs), a kind of antigen presenting cells, which play a key role in the induction of allergic airway inflammation, are privileged targets for pathogen associated molecular patterns (PAMPs). During the allergic responses, engagement of TLRs on DCs determines the Th2 polarization of the T cells. TLR signaling in mast cells increases the release of IL-5, and TLR activation of airway epithelial cells forces the generation of proallergic Th2 type of cytokines. Although these responses aim to protect the host, they may also result in inflammatory tissue damage in the airway. Under certain conditions, stimulation of TLRs, in particular, TLR9, may reduce Th2-dependent allergic inflammation by induction of Th1 responses. Therefore, understanding the complex regulatory roles of TLRs in the pathogenesis of allergic airway inflammation should facilitate the development of preventive and therapeutic measures for asthmatic patients. PMID:21624504

  5. A mannose receptor mediates mannosyl-rich glycoprotein-induced mitogenesis in bovine airway smooth muscle cells.

    PubMed Central

    Lew, D B; Songu-Mize, E; Pontow, S E; Stahl, P D; Rattazzi, M C

    1994-01-01

    The putative mannose receptor (MR), previously implicated in mannosyl-rich glycoprotein-induced mitogenesis in bovine airway smooth muscle (ASM) cells, was studied to determine its properties. Specific binding of the mitogenic neoglycoprotein, mannosylated bovine serum albumin (Man-BSA) to ASM cells was saturable, with an apparent Kd = 5.0 x 10(-8) M. Cell-bound ManBSA-colloidal gold conjugate was localized by electron microscopy to clathrin-coated pits on the cell surface, and was found to undergo internalization to endosomes; this was inhibitable by weak bases and swainsonine, that also inhibited ligand-induced mitogenesis. The ASM-MR, isolated by mannose-affinity chromatography, had the same apparent molecular mass as the macrophage (Mø) MR (M(r) = 175 kD), and was immunoprecipitated by an anti-MøMR immune serum. This antiserum blocked 125I-labeled-ManBSA binding to intact ASM cells, stimulated mitogenesis, and immunolocalized the ASM-MR in cytoplasmic vesicles compatible with endosomes. A monoclonal antibody directed against the MøMR also reacted with the ASM-MR; like the polyclonal antibodies, it stimulated mitogenesis as effectively as beta-hexosaminidases. These data indicate that the ASM-MR shares a number of functional and structural properties with the MøMR and suggest that similar receptors may have different main functions in different cells. Images PMID:7962531

  6. Induction of cyclo-oxygenase-2 by cytokines in human cultured airway smooth muscle cells: novel inflammatory role of this cell type

    PubMed Central

    Belvisi, Maria G; Saunders, Michael A; Haddad, El-Bdaoui; Hirst, Stuart J; Yacoub, Magdi H; Barnes, Peter J; Mitchell, Jane A

    1997-01-01

    Cyclo-oxygenase (COX) is the enzyme that converts arachidonic acid to prostaglandin H2 (PGH2) which can then be further metabolized to prostanoids which modulate various airway functions. COX exists in at least two isoforms. COX-1 is expressed constitutively, whereas COX-2 is expressed in response to pro-inflammatory stimuli. Prostanoids are produced under physiological and pathophysiological conditions by many cell types in the lung. However, the regulation of the different COX isoforms in human airway smooth muscle (HASM) cells has not yet been determined.COX-1 and COX-2 protein were measured by Western blot analysis with specific antibodies for COX-1 and COX-2. COX-2 mRNA levels were assessed by Northern blot analysis by use of a COX-2 cDNA probe. COX activity was determined by measuring conversion of either endogenous or exogenous arachidonic acid to three metabolites, PGE2, thromboxane B2 or 6-ketoPGF1α by radioimmunoassay.Under control culture conditions HASM cells expressed COX-1, but not COX-2, protein. However, a mixture of cytokines (interleukin-1β (IL-1β), tumour necrosis factor α (TNFα) and interferon γ (IFNγ) each at 10 ng ml−1) induced COX-2 mRNA expression, which was maximal at 12 h and inhibited by dexamethasone (1 μM; added 30 min before the cytokines). Furthermore, COX-2 protein was detected 24 h after the cytokine treatment and the expression of this protein was also inhibited by dexamethasone (1 μM) and cyclohexamide (10 μg ml−1; added 30 min before the cytokines).Untreated HASM cells released low or undetectable amounts of all COX metabolites measured over a 24 h period. Incubation of the cells with the cytokine mixture (IL-1β, TNFα, IFNγ each at 10 ng ml−1 for 24 h) caused the accumulation of PGE2 and 6-keto-PGF1α.In experiments where COX-2 metabolized endogenous stores of arachidonic acid, treatment of HASM cells with IL-1β in combination with TNFα caused a similar release of PGE2 to that when

  7. Regulation of Murine Airway Surface Liquid Volume by CFTR and Ca2+-activated Cl− Conductances

    PubMed Central

    Tarran, Robert; Loewen, Matthew E.; Paradiso, Anthony M.; Olsen, John C.; Gray, Micheal A.; Argent, Barry E.; Boucher, Richard C.; Gabriel, Sherif E.

    2002-01-01

    Two Cl− conductances have been described in the apical membrane of both human and murine proximal airway epithelia that are thought to play predominant roles in airway hydration: (1) CFTR, which is cAMP regulated and (2) the Ca2+-activated Cl− conductance (CaCC) whose molecular identity is uncertain. In addition to second messenger regulation, cross talk between these two channels may also exist and, whereas CFTR is absent or defective in cystic fibrosis (CF) airways, CaCC is preserved, and may even be up-regulated. Increased CaCC activity in CF airways is controversial. Hence, we have investigated the effects of CFTR on CaCC activity and have also assessed the relative contributions of these two conductances to airway surface liquid (ASL) height (volume) in murine tracheal epithelia. We find that CaCC is up-regulated in intact murine CF tracheal epithelia, which leads to an increase in UTP-mediated Cl−/volume secretion. This up-regulation is dependent on cell polarity and is lost in nonpolarized epithelia. We find no role for an increased electrical driving force in CaCC up-regulation but do find an increased Ca2+ signal in response to mucosal nucleotides that may contribute to the increased Cl−/volume secretion seen in intact epithelia. CFTR plays a critical role in maintaining ASL height under basal conditions and accordingly, ASL height is reduced in CF epithelia. In contrast, CaCC does not appear to significantly affect basal ASL height, but does appear to be important in regulating ASL height in response to released agonists (e.g., mucosal nucleotides). We conclude that both CaCC and the Ca2+ signal are increased in CF airway epithelia, and that they contribute to acute but not basal regulation of ASL height. PMID:12198094

  8. Accelerometer based calf muscle pump activity monitoring.

    PubMed

    O'Donovan, Karol J; O'Keeffe, Derek T; Grace, Pierce A; Lyons, Gerard M

    2005-10-01

    Long distance travel is associated with increased risk of deep vein thrombosis (DVT). There is an increased risk of travel related DVT in passengers with a predisposition to thrombosis. Assisting blood circulation in the lower limb will reduce the risk of DVT. Leg exercises are recommended as a DVT preventative measure while flying but this fails to account for a passenger who is distracted by in flight entertainment or who falls asleep for an extended period. A method for monitoring calf muscle pump activity using accelerometers has been developed and evaluated. The proposed technique could be used to alert the traveller that there is a need to exercise their calf muscle, thus reducing the risk of DVT. PMID:16139770

  9. Functional Effects of WNT1-Inducible Signaling Pathway Protein-1 on Bronchial Smooth Muscle Cell Migration and Proliferation in OVA-Induced Airway Remodeling.

    PubMed

    Yang, Mingjin; Du, Yuejun; Xu, Zhibo; Jiang, Youfan

    2016-02-01

    Upregulation of WISP1 has been demonstrated in lung remodeling. Moreover, it has been recently found that some signaling components of WNT pathway can activate GSK3β signaling to mediate remodeling of airway smooth muscle (ASM) in asthma. Therefore, we hypothesized that WISP1, a signaling molecule downstream of the WNT signaling pathway, is involved in PI3K/GSK3β signaling to mediate ASM remodeling in asthma. Our results showed that WISP1 depletion partly suppressed OVA-induced ASM hypertrophy in vivo. In vitro, WISP1 could induce hBSMC hypertrophy and proliferation, accompanied by upregulation of levels of PI3K, p-Akt, p-GSK3β, and its own expression. TGF-β treatment could increase expression of PI3K, p-Akt, p-GSK3β, and WISP1. SH-5 treatment could partly suppress TGF-β-induced hypertrophy and proliferation of hBSMC, and depress expression of p-GSK3β and WISP1. In conclusion, WISP1 may be a potential inducer of ASM proliferation and hypertrophy in asthma. The pro-remodeling effect of WISP1 is likely due to be involved in PI3K-GSK3β-dependent noncanonical TGF-β signaling. PMID:26242865

  10. Relative Activity of Abdominal Muscles during Commonly Prescribed Strengthening Exercises.

    ERIC Educational Resources Information Center

    Willett, Gilbert M.; Hyde, Jennifer E.; Uhrlaub, Michael B.; Wendel, Cara L.; Karst, Gregory M.

    2001-01-01

    Examined the relative electromyographic (EMG) activity of upper and lower rectus abdominis (LRA) and external oblique (EOA) muscles during five abdominal strengthening exercises. Isometric and dynamic EMG data indicated that abdominal strengthening exercises activated various abdominal muscle groups. For the LRA and EOA muscle groups, there were…

  11. Extracellular acidification induces connective tissue growth factor production through proton-sensing receptor OGR1 in human airway smooth muscle cells

    SciTech Connect

    Matsuzaki, Shinichi; Ishizuka, Tamotsu; Yamada, Hidenori; Kamide, Yosuke; Hisada, Takeshi; Ichimonji, Isao; Aoki, Haruka; Yatomi, Masakiyo; Komachi, Mayumi; Tsurumaki, Hiroaki; Ono, Akihiro; Koga, Yasuhiko; Dobashi, Kunio; Mogi, Chihiro; Sato, Koichi; Tomura, Hideaki; Mori, Masatomo; Okajima, Fumikazu

    2011-10-07

    Highlights: {yields} The involvement of extracellular acidification in airway remodeling was investigated. {yields} Extracellular acidification alone induced CTGF production in human ASMCs. {yields} Extracellular acidification enhanced TGF-{beta}-induced CTGF production in human ASMCs. {yields} Proton-sensing receptor OGR1 was involved in acidic pH-stimulated CTGF production. {yields} OGR1 may play an important role in airway remodeling in asthma. -- Abstract: Asthma is characterized by airway inflammation, hyper-responsiveness and remodeling. Extracellular acidification is known to be associated with severe asthma; however, the role of extracellular acidification in airway remodeling remains elusive. In the present study, the effects of acidification on the expression of connective tissue growth factor (CTGF), a critical factor involved in the formation of extracellular matrix proteins and hence airway remodeling, were examined in human airway smooth muscle cells (ASMCs). Acidic pH alone induced a substantial production of CTGF, and enhanced transforming growth factor (TGF)-{beta}-induced CTGF mRNA and protein expression. The extracellular acidic pH-induced effects were inhibited by knockdown of a proton-sensing ovarian cancer G-protein-coupled receptor (OGR1) with its specific small interfering RNA and by addition of the G{sub q/11} protein-specific inhibitor, YM-254890, or the inositol-1,4,5-trisphosphate (IP{sub 3}) receptor antagonist, 2-APB. In conclusion, extracellular acidification induces CTGF production through the OGR1/G{sub q/11} protein and inositol-1,4,5-trisphosphate-induced Ca{sup 2+} mobilization in human ASMCs.

  12. Muscle activity pattern dependent pain development and alleviation.

    PubMed

    Sjøgaard, Gisela; Søgaard, Karen

    2014-12-01

    Muscle activity is for decades considered to provide health benefits irrespectively of the muscle activity pattern performed and whether it is during e.g. sports, transportation, or occupational work tasks. Accordingly, the international recommendations for public health-promoting physical activity do not distinguish between occupational and leisure time physical activity. However, in this body of literature, attention has not been paid to the extensive documentation on occupational physical activity imposing a risk of impairment of health - in particular musculoskeletal health in terms of muscle pain. Focusing on muscle activity patterns and musculoskeletal health it is pertinent to elucidate the more specific aspects regarding exposure profiles and body regional pain. Static sustained muscle contraction for prolonged periods often occurs in the neck/shoulder area during occupational tasks and may underlie muscle pain development in spite of rather low relative muscle load. Causal mechanisms include a stereotype recruitment of low threshold motor units (activating type 1 muscle fibers) characterized by a lack of temporal as well as spatial variation in recruitment. In contrast during physical activities at leisure and sport the motor recruitment patterns are more dynamic including regularly relatively high muscle forces - also activating type 2 muscles fibers - as well as periods of full relaxation even of the type 1 muscle fibers. Such activity is unrelated to muscle pain development if adequate recovery is granted. However, delayed muscle soreness may develop following intensive eccentric muscle activity (e.g. down-hill skiing) with peak pain levels in thigh muscles 1-2 days after the exercise bout and a total recovery within 1 week. This acute pain profile is in contrast to the chronic muscle pain profile related to repetitive monotonous work tasks. The painful muscles show adverse functional, morphological, hormonal, as well as metabolic characteristics. Of

  13. Demonstrating Electrical Activity in Nerve and Muscle. Part II

    ERIC Educational Resources Information Center

    Robinson, D. J.

    1976-01-01

    Describes the construction of an amplifier and force transducer that can be used to demonstrate electrical activity in nerve and muscle using the gastrocnemius muscle and sciatic nerve of the frog. (MLH)

  14. Muscle activation of paraspinal muscles in different types of high heels during standing

    PubMed Central

    Han, Dongwook

    2015-01-01

    [Purpose] This study researched the effects of different types of high heels on the muscles surrounding the cervical spine, the thoracic spine, and the lumbar spine by analyzing muscle activation of the paraspinal muscles during standing while wearing high heels. The high heels were all of the same height: 8 cm. [Subjects and Methods] The 28 subjects in this experiment were females in their 20s with a foot size of 225–230 mm and a normal gait pattern. To measure the muscle activation of the paraspinal muscles, EMG electrodes were attached on the paraspinal muscles around C6, T7, and L5. The muscle activation during standing while wearing 8-cm-high wedge heels, setback heels, and French heels was then measured. The measurements were performed 3 times each, and the mean value was used for analysis. [Results] The levels of muscle activation of the paraspinal muscles induced by standing on wedge heels, setback heels, and French heels in the cervical and lumbar areas were significantly higher than those induced by standing on bare feet. But there was no significant difference according to the heel types. [Conclusion] The height of the heels presented a greater variable than the width of the heels on the muscle activation of paraspinal muscles. Therefore, wearing high heels is not recommended for those who have pain or functional problems in the cervical and/or lumbar spine. PMID:25642040

  15. PLUNC Is a Novel Airway Surfactant Protein with Anti-Biofilm Activity

    PubMed Central

    Penterman, Jon; Mizrachi, Dario; Singh, Pradeep K.; Mallampalli, Rama K.; Ramaswamy, S.; McCray, Paul B.

    2010-01-01

    Background The PLUNC (“Palate, lung, nasal epithelium clone”) protein is an abundant secretory product of epithelia present throughout the conducting airways of humans and other mammals, which is evolutionarily related to the lipid transfer/lipopolysaccharide binding protein (LT/LBP) family. Two members of this family - the bactericidal/permeability increasing protein (BPI) and the lipopolysaccharide binding protein (LBP) - are innate immune molecules with recognized roles in sensing and responding to Gram negative bacteria, leading many to propose that PLUNC may play a host defense role in the human airways. Methodology/Principal Findings Based on its marked hydrophobicity, we hypothesized that PLUNC may be an airway surfactant. We found that purified recombinant human PLUNC greatly enhanced the ability of aqueous solutions to spread on a hydrophobic surface. Furthermore, we discovered that PLUNC significantly reduced surface tension at the air-liquid interface in aqueous solutions, indicating novel and biologically relevant surfactant properties. Of note, surface tensions achieved by adding PLUNC to solutions are very similar to measurements of the surface tension in tracheobronchial secretions from humans and animal models. Because surfactants of microbial origin can disperse matrix-encased bacterial clusters known as biofilms [1], we hypothesized that PLUNC may also have anti-biofilm activity. We found that, at a physiologically relevant concentration, PLUNC inhibited biofilm formation by the airway pathogen Pseudomonas aeruginosa in an in vitro model. Conclusions/Significance Our data suggest that the PLUNC protein contributes to the surfactant properties of airway secretions, and that this activity may interfere with biofilm formation by an airway pathogen. PMID:20161732

  16. A New Approach for the Study of Lung Smooth Muscle Phenotypes and Its Application in a Murine Model of Allergic Airway Inflammation

    PubMed Central

    Paez-Cortez, Jesus; Krishnan, Ramaswamy; Arno, Anneliese; Aven, Linh; Ram-Mohan, Sumati; Patel, Kruti R.; Lu, Jining; King, Oliver D.; Ai, Xingbin; Fine, Alan

    2013-01-01

    Phenotypes of lung smooth muscle cells in health and disease are poorly characterized. This is due, in part, to a lack of methodologies that allow for the independent and direct isolation of bronchial smooth muscle cells (BSMCs) and vascular smooth muscle cells (VSMCs) from the lung. In this paper, we describe the development of a bi-fluorescent mouse that permits purification of these two cell populations by cell sorting. By subjecting this mouse to an acute allergen based-model of airway inflammation that exhibits many features of asthma, we utilized this tool to characterize the phenotype of so-called asthmatic BSMCs. First, we examined the biophysical properties of single BSMCs from allergen sensitized mice and found increases in basal tone and cell size that were sustained ex vivo. We then generated for the first time, a comprehensive characterization of the global gene expression changes in BSMCs isolated from the bi-fluorescent mice with allergic airway inflammation. Using statistical methods and pathway analysis, we identified a number of differentially expressed mRNAs in BSMCs from allergen sensitized mice that code for key candidate proteins underlying changes in matrix formation, contractility, and immune responses. Ultimately, this tool will provide direction and guidance for the logical development of new markers and approaches for studying human lung smooth muscle. PMID:24040256

  17. Stochastic modelling of muscle recruitment during activity.

    PubMed

    Martelli, Saulo; Calvetti, Daniela; Somersalo, Erkki; Viceconti, Marco

    2015-04-01

    Muscle forces can be selected from a space of muscle recruitment strategies that produce stable motion and variable muscle and joint forces. However, current optimization methods provide only a single muscle recruitment strategy. We modelled the spectrum of muscle recruitment strategies while walking. The equilibrium equations at the joints, muscle constraints, static optimization solutions and 15-channel electromyography (EMG) recordings for seven walking cycles were taken from earlier studies. The spectrum of muscle forces was calculated using Bayesian statistics and Markov chain Monte Carlo (MCMC) methods, whereas EMG-driven muscle forces were calculated using EMG-driven modelling. We calculated the differences between the spectrum and EMG-driven muscle force for 1-15 input EMGs, and we identified the muscle strategy that best matched the recorded EMG pattern. The best-fit strategy, static optimization solution and EMG-driven force data were compared using correlation analysis. Possible and plausible muscle forces were defined as within physiological boundaries and within EMG boundaries. Possible muscle and joint forces were calculated by constraining the muscle forces between zero and the peak muscle force. Plausible muscle forces were constrained within six selected EMG boundaries. The spectrum to EMG-driven force difference increased from 40 to 108 N for 1-15 EMG inputs. The best-fit muscle strategy better described the EMG-driven pattern (R (2) = 0.94; RMSE = 19 N) than the static optimization solution (R (2) = 0.38; RMSE = 61 N). Possible forces for 27 of 34 muscles varied between zero and the peak muscle force, inducing a peak hip force of 11.3 body-weights. Plausible muscle forces closely matched the selected EMG patterns; no effect of the EMG constraint was observed on the remaining muscle force ranges. The model can be used to study alternative muscle recruitment strategies in both physiological and pathophysiological neuromotor conditions. PMID

  18. Stochastic modelling of muscle recruitment during activity

    PubMed Central

    Martelli, Saulo; Calvetti, Daniela; Somersalo, Erkki; Viceconti, Marco

    2015-01-01

    Muscle forces can be selected from a space of muscle recruitment strategies that produce stable motion and variable muscle and joint forces. However, current optimization methods provide only a single muscle recruitment strategy. We modelled the spectrum of muscle recruitment strategies while walking. The equilibrium equations at the joints, muscle constraints, static optimization solutions and 15-channel electromyography (EMG) recordings for seven walking cycles were taken from earlier studies. The spectrum of muscle forces was calculated using Bayesian statistics and Markov chain Monte Carlo (MCMC) methods, whereas EMG-driven muscle forces were calculated using EMG-driven modelling. We calculated the differences between the spectrum and EMG-driven muscle force for 1–15 input EMGs, and we identified the muscle strategy that best matched the recorded EMG pattern. The best-fit strategy, static optimization solution and EMG-driven force data were compared using correlation analysis. Possible and plausible muscle forces were defined as within physiological boundaries and within EMG boundaries. Possible muscle and joint forces were calculated by constraining the muscle forces between zero and the peak muscle force. Plausible muscle forces were constrained within six selected EMG boundaries. The spectrum to EMG-driven force difference increased from 40 to 108 N for 1–15 EMG inputs. The best-fit muscle strategy better described the EMG-driven pattern (R2 = 0.94; RMSE = 19 N) than the static optimization solution (R2 = 0.38; RMSE = 61 N). Possible forces for 27 of 34 muscles varied between zero and the peak muscle force, inducing a peak hip force of 11.3 body-weights. Plausible muscle forces closely matched the selected EMG patterns; no effect of the EMG constraint was observed on the remaining muscle force ranges. The model can be used to study alternative muscle recruitment strategies in both physiological and pathophysiological neuromotor conditions. PMID:25844155

  19. Selective targeting of TGF-β activation to treat fibroinflammatory airway disease.

    PubMed

    Minagawa, Shunsuke; Lou, Jianlong; Seed, Robert I; Cormier, Anthony; Wu, Shenping; Cheng, Yifan; Murray, Lynne; Tsui, Ping; Connor, Jane; Herbst, Ronald; Govaerts, Cedric; Barker, Tyren; Cambier, Stephanie; Yanagisawa, Haruhiko; Goodsell, Amanda; Hashimoto, Mitsuo; Brand, Oliver J; Cheng, Ran; Ma, Royce; McKnelly, Kate J; Wen, Weihua; Hill, Arthur; Jablons, David; Wolters, Paul; Kitamura, Hideya; Araya, Jun; Barczak, Andrea J; Erle, David J; Reichardt, Louis F; Marks, James D; Baron, Jody L; Nishimura, Stephen L

    2014-06-18

    Airway remodeling, caused by inflammation and fibrosis, is a major component of chronic obstructive pulmonary disease (COPD) and currently has no effective treatment. Transforming growth factor-β (TGF-β) has been widely implicated in the pathogenesis of airway remodeling in COPD. TGF-β is expressed in a latent form that requires activation. The integrin αvβ8 (encoded by the itgb8 gene) is a receptor for latent TGF-β and is essential for its activation. Expression of integrin αvβ8 is increased in airway fibroblasts in COPD and thus is an attractive therapeutic target for the treatment of airway remodeling in COPD. We demonstrate that an engineered optimized antibody to human αvβ8 (B5) inhibited TGF-β activation in transgenic mice expressing only human and not mouse ITGB8. The B5 engineered antibody blocked fibroinflammatory responses induced by tobacco smoke, cytokines, and allergens by inhibiting TGF-β activation. To clarify the mechanism of action of B5, we used hydrodynamic, mutational, and electron microscopic methods to demonstrate that αvβ8 predominantly adopts a constitutively active, extended-closed headpiece conformation. Epitope mapping and functional characterization of B5 revealed an allosteric mechanism of action due to locking-in of a low-affinity αvβ8 conformation. Collectively, these data demonstrate a new model for integrin function and present a strategy to selectively target the TGF-β pathway to treat fibroinflammatory airway diseases. PMID:24944194

  20. Selective Targeting of TGF-β Activation to Treat Fibroinflammatory Airway Disease

    PubMed Central

    Minagawa, Shunsuke; Lou, Jianlong; Seed, Robert I.; Cormier, Anthony; Wu, Shenping; Cheng, Yifan; Murray, Lynne; Tsui, Ping; Connor, Jane; Herbst, Ronald; Govaerts, Cedric; Barker, Tyren; Cambier, Stephanie; Yanagisawa, Haruhiko; Goodsell, Amanda; Hashimoto, Mitsuo; Brand, Oliver J.; Cheng, Ran; Ma, Royce; McKnelly, Kate J.; Wen, Weihua; Hill, Arthur; Jablons, David; Wolters, Paul; Kitamura, Hideya; Araya, Jun; Barczak, Andrea J.; Erle, David J.; Reichardt, Louis F.; Marks, James D.; Baron, Jody L.; Nishimura, Stephen L.

    2015-01-01

    Airway remodeling, caused by inflammation and fibrosis, is a major component of chronic obstructive pulmonary disease (COPD) and currently has no effective treatment. Transforming growth factor–β (TGF-β) has been widely implicated in the pathogenesis of airway remodeling in COPD. TGF-β is expressed in a latent form that requires activation. The integrin αvβ8 (encoded by the itgb8 gene) is a receptor for latent TGF-β and is essential for its activation. Expression of integrin αvβ8 is increased in airway fibroblasts in COPD and thus is an attractive therapeutic target for the treatment of airway remodeling in COPD. We demonstrate that an engineered optimized antibody to human αvβ8 (B5) inhibited TGF-β activation in transgenic mice expressing only human and not mouse ITGB8. The B5 engineered antibody blocked fibroinflammatory responses induced by tobacco smoke, cytokines, and allergens by inhibiting TGF-β activation. To clarify the mechanism of action of B5, we used hydrodynamic, mutational, and electron microscopic methods to demonstrate that αvβ8 predominantly adopts a constitutively active, extended-closed headpiece conformation. Epitope mapping and functional characterization of B5 revealed an allosteric mechanism of action due to locking-in of a low-affinity αvβ8 conformation. Collectively, these data demonstrate a new model for integrin function and present a strategy to selectively target the TGF-β pathway to treat fibroinflammatory airway diseases. PMID:24944194

  1. Influence of posterior cricoarytenoid muscle activity on pressure-flow relationship of the larynx.

    PubMed

    Tully, A; Brancatisano, A; Loring, S H; Engel, L A

    1991-05-01

    We examined the effect of posterior cricoarytenoid (PCA) muscle activity on the pressure-flow (PV) relationship of the larynx in five anesthetized tracheostomized dogs. The PCA activity was recorded using bipolar fine-wire electrodes, expressed as a percentage of the quiet breathing level and altered by mechanical ventilation, changes in lung volume, and chest wall compression. Subglottic pressure was recorded while a constant flow of air was passed through the upper airway. In the absence of PCA activity the PV relationship was alinear and could be described by a power function (P = K0Va, where K0 and a are constants). The slope of the log P-log V plots in the absence of PCA and thyroarytenoid activity was 1.83 +/- 0.02 (SD), whereas with increasing PCA activity it was 1.88 +/- 0.11. An effective hydraulic diameter (DH) was calculated for 20% increments of PCA activity, and in two dogs glottic diameter (Dg) was calculated from glottic area measurements obtained by fiber-optic laryngoscopy. Both DH and Dg increased linearly with increasing PCA activity. Denervation of the cricothyroid muscle had no systematic effect on laryngeal resistance. The results indicate that the PV relationship of the larynx may be described by a power function with a single exponent, the magnitude of which is independent of glottic dilator muscle activity and consistent with orifice flow. However, laryngeal diameter increases linearly with PCA activity in the range studied. PMID:1864806

  2. Ciliary muscle contraction force and trapezius muscle activity during manual tracking of a moving visual target.

    PubMed

    Domkin, Dmitry; Forsman, Mikael; Richter, Hans O

    2016-06-01

    Previous studies have shown an association of visual demands during near work and increased activity of the trapezius muscle. Those studies were conducted under stationary postural conditions with fixed gaze and artificial visual load. The present study investigated the relationship between ciliary muscle contraction force and trapezius muscle activity across individuals during performance of a natural dynamic motor task under free gaze conditions. Participants (N=11) tracked a moving visual target with a digital pen on a computer screen. Tracking performance, eye refraction and trapezius muscle activity were continuously measured. Ciliary muscle contraction force was computed from eye accommodative response. There was a significant Pearson correlation between ciliary muscle contraction force and trapezius muscle activity on the tracking side (0.78, p<0.01) and passive side (0.64, p<0.05). The study supports the hypothesis that high visual demands, leading to an increased ciliary muscle contraction during continuous eye-hand coordination, may increase trapezius muscle tension and thus contribute to the development of musculoskeletal complaints in the neck-shoulder area. Further experimental studies are required to clarify whether the relationship is valid within each individual or may represent a general personal trait, when individuals with higher eye accommodative response tend to have higher trapezius muscle activity. PMID:26746010

  3. Targeting the γ-Aminobutyric Acid A Receptor α4 Subunit in Airway Smooth Muscle to Alleviate Bronchoconstriction.

    PubMed

    Yocum, Gene T; Gallos, George; Zhang, Yi; Jahan, Rajwana; Stephen, Michael Rajesh; Varagic, Zdravko; Puthenkalam, Roshan; Ernst, Margot; Cook, James M; Emala, Charles W

    2016-04-01

    We previously demonstrated that airway smooth muscle (ASM) cells express γ-aminobutyric acid A receptors (GABAARs), and that GABAAR agonists acutely relax ASM. Among the GABAAR α subunits, human ASM cells express only α4 and α5, providing the opportunity for selective pharmacologic targeting. Novel GABAAR-positive allosteric modulators designed for enhanced α4/α6 subunit selectivity were synthesized using iterative computational analyses (CMD-45 and XHe-III-74). Studies using oocyte heterologous expression systems confirmed that CMD-45 and XHe-III-74 led to significantly greater augmentation of currents induced by a 3% maximal effective concentration (EC3) of GABA [EC3]-induced currents in oocytes expressing α4 or α6 subunits (along with β3 and γ2) compared with other α subunits. CMD-45 and XHe-III-74 also led to greater ex vivo relaxation of contracted wild-type mouse tracheal rings compared with tracheal rings from GABAAR α4 subunit (Gabra4) knockout mice. Furthermore, CMD-45 and XHe-III-74 significantly relaxed precontracted human ASM ex vivo, and, at a low concentration, both ligands led to a significant leftward shift in albuterol-mediated ASM relaxation. In vivo, inhaled XHe-III-74 reduced respiratory system resistance in an asthmatic mouse model. Pretreatment of human ASM cells with CMD-45 and XHe-III-74 inhibited histamine-induced increases in intracellular calcium concentrations in vitro, an effect that was lost when calcium was omitted from the extracellular buffer, suggesting that inhibition of calcium influx due to alterations in plasma membrane potential may play a role in the mechanism of ASM relaxation. Selective targeting of the GABAAR α4 subunit with inhaled ligands may be a novel therapeutic pathway to treat bronchoconstriction, while avoiding sedative central nervous system effects, which are largely mediated by α1-3 subunit-containing GABAARs in the brain. PMID:26405827

  4. The small heat shock-related protein, HSP20, is a cAMP-dependent protein kinase substrate that is involved in airway smooth muscle relaxation

    PubMed Central

    Komalavilas, Padmini; Penn, Raymond B.; Flynn, Charles R.; Thresher, Jeffrey; Lopes, Luciana B.; Furnish, Elizabeth J.; Guo, Manhong; Pallero, Manuel A.; Murphy-Ullrich, Joanne E.; Brophy, Colleen M.

    2009-01-01

    Activation of the cAMP/cAMP-dependent PKA pathway leads to relaxation of airway smooth muscle (ASM). The purpose of this study was to examine the role of the small heat shock-related protein HSP20 in mediating PKA-dependent ASM relaxation. Human ASM cells were engineered to constitutively express a green fluorescent protein-PKA inhibitory fusion protein (PKI-GFP) or GFP alone. Activation of the cAMP-dependent signaling pathways by isoproterenol (ISO) or forskolin led to increases in the phosphorylation of HSP20 in GFP but not PKI-GFP cells. Forskolin treatment in GFP but not PKI-GFP cells led to a loss of central actin stress fibers and decreases in the number of focal adhesion complexes. This loss of stress fibers was associated with dephosphorylation of the actin-depolymerizing protein cofilin in GFP but not PKI-GFP cells. To confirm that phosphorylated HSP20 plays a role in PKA-induced ASM relaxation, intact strips of bovine ASM were precontracted with serotonin followed by ISO. Activation of the PKA pathway led to relaxation of bovine ASM, which was associated with phosphorylation of HSP20 and dephosphorylation of cofilin. Finally, treatment with phosphopeptide mimetics of HSP20 possessing a protein transduction domain partially relaxed precontracted bovine ASM strips. In summary, ISO-induced phosphorylation of HSP20 or synthetic phosphopeptide analogs of HSP20 decreases phosphorylation of cofilin and disrupts actin in ASM, suggesting that one possible mechanism by which HSP20 mediates ASM relaxation is via regulation of actin filament dynamics. PMID:17993590

  5. Airway mucus obstruction triggers macrophage activation and matrix metalloproteinase 12-dependent emphysema.

    PubMed

    Trojanek, Joanna B; Cobos-Correa, Amanda; Diemer, Stefanie; Kormann, Michael; Schubert, Susanne C; Zhou-Suckow, Zhe; Agrawal, Raman; Duerr, Julia; Wagner, Claudius J; Schatterny, Jolanthe; Hirtz, Stephanie; Sommerburg, Olaf; Hartl, Dominik; Schultz, Carsten; Mall, Marcus A

    2014-11-01

    Whereas cigarette smoking remains the main risk factor for emphysema, recent studies in β-epithelial Na(+) channel-transgenic (βENaC-Tg) mice demonstrated that airway surface dehydration, a key pathophysiological mechanism in cystic fibrosis (CF), caused emphysema in the absence of cigarette smoke exposure. However, the underlying mechanisms remain unknown. The aim of this study was to elucidate mechanisms of emphysema formation triggered by airway surface dehydration. We therefore used expression profiling, genetic and pharmacological inhibition, Foerster resonance energy transfer (FRET)-based activity assays, and genetic association studies to identify and validate emphysema candidate genes in βENaC-Tg mice and patients with CF. We identified matrix metalloproteinase 12 (Mmp12) as a highly up-regulated gene in lungs from βENaC-Tg mice, and demonstrate that elevated Mmp12 expression was associated with progressive emphysema formation, which was reduced by genetic deletion and pharmacological inhibition of MMP12 in vivo. By using FRET reporters, we show that MMP12 activity was elevated on the surface of airway macrophages in bronchoalveolar lavage from βENaC-Tg mice and patients with CF. Furthermore, we demonstrate that a functional polymorphism in MMP12 (rs2276109) was associated with severity of lung disease in CF. Our results suggest that MMP12 released by macrophages activated on dehydrated airway surfaces may play an important role in emphysema formation in the absence of cigarette smoke exposure, and may serve as a therapeutic target in CF and potentially other chronic lung diseases associated with airway mucus dehydration and obstruction. PMID:24828142

  6. Control of ankle extensor muscle activity in walking cats.

    PubMed

    Hatz, Kathrin; Mombaur, Katja; Donelan, J Maxwell

    2012-11-01

    Our objective was to gain insight into the relative importance of feedforward control and different proprioceptive feedback pathways to ongoing ankle extensor activity during walking in the conscious cat. We asked whether the modulation of stance phase muscle activity is due primarily to proprioceptive feedback and whether the same proprioceptive gains and feedforward commands can automatically generate the muscle activity required for changes in walking slope. To test these hypotheses, we analyzed previously collected muscle activity and mechanics data from cats with an isolated medial gastrocnemius muscle walking along a sloped pegway. Models of proprioceptor dynamics predicted afferent activity from the measured muscle mechanics. We modeled muscle activity as the weighted sum of the activity predicted from the different proprioceptive pathways and a simple model of central drive. We determined the unknown model parameters using optimization procedures that minimized the error between the predicted and measured muscle activity. We found that the modulation of muscle activity within the stance phase and across walking slopes is indeed well described by neural control that employs constant central drive and constant proprioceptive feedback gains. Furthermore, it is force feedback from Ib afferents that is primarily responsible for modulating muscle activity; group II afferent feedback makes a small contribution to tonic activity, and Ia afferent feedback makes no contribution. Force feedback combined with tonic central drive appears to provide a simple control mechanism for automatically compensating for changes in terrain without requiring different commands from the brain or even modification of central nervous system gains. PMID:22933727

  7. The influence of experimentally induced pain on shoulder muscle activity.

    PubMed

    Diederichsen, Louise Pyndt; Winther, Annika; Dyhre-Poulsen, Poul; Krogsgaard, Michael R; Nørregaard, Jesper

    2009-04-01

    Muscle function is altered in painful shoulder conditions. However, the influence of shoulder pain on muscle coordination of the shoulder has not been fully clarified. The aim of the present study was to examine the effect of experimentally induced shoulder pain on shoulder muscle function. Eleven healthy men (range 22-27 years), with no history of shoulder or cervical problems, were included in the study. Pain was induced by 5% hypertonic saline injections into the supraspinatus muscle or subacromially. Seated in a shoulder machine, subjects performed standardized concentric abduction (0 degrees -105 degrees) at a speed of approximately 120 degrees/s, controlled by a metronome. During abduction, electromyographic (EMG) activity was recorded by intramuscular wire electrodes inserted in two deeply located shoulder muscles and by surface-electrodes over six superficially located shoulder muscles. EMG was recorded before pain, during pain and after pain had subsided and pain intensity was continuously scored on a visual analog scale (VAS). During abduction, experimentally induced pain in the supraspinatus muscle caused a significant decrease in activity of the anterior deltoid, upper trapezius and the infraspinatus and an increase in activity of lower trapezius and latissimus dorsi muscles. Following subacromial injection a significantly increased muscle activity was seen in the lower trapezius, the serratus anterior and the latissimus dorsi muscles. In conclusion, this study shows that acute pain both subacromially and in the supraspinatus muscle modulates coordination of the shoulder muscles during voluntary movements. During painful conditions, an increased activity was detected in the antagonist (latissimus), which support the idea that localized pain affects muscle activation in a way that protects the painful structure. Further, the changes in muscle activity following subacromial pain induction tend to expand the subacromial space and thereby decrease the load

  8. Respiratory muscle activity and oxygenation during sleep in patients with muscle weakness.

    PubMed

    White, J E; Drinnan, M J; Smithson, A J; Griffiths, C J; Gibson, G J

    1995-05-01

    Patients with respiratory muscle weakness show nocturnal hypoventilation, with oxygen desaturation particularly during rapid eye movement (REM) sleep, but evidence in individuals with isolated bilateral diaphragmatic paresis (BDP) is conflicting. The effect of sleep on relative activity of the different respiratory muscles of such patients and, consequently, the precise mechanisms causing desaturation have not been clarified. We have studied eight patients, four with generalized muscle weakness and four with isolated BDP during nocturnal sleep with measurements including oxygen saturation and surface electromyographic (EMG) activity of various respiratory muscle groups. Nocturnal oxygenation correlated inversely with postural fall in vital capacity, an index of diaphragmatic strength. During REM sleep, hypopnoea and desaturation occurred particularly during periods of rapid eye movements (phasic REM sleep). In most subjects, such events were "central" in type and associated with marked suppression of intercostal muscle activity, but two subjects had recurrent desaturation due to "obstructive" hypopnoea and/or apnoea. Expiratory activity of the external oblique muscle was present whilst awake and during non-rapid eye movement (NREM) sleep in seven of the eight subjects in the semirecumbent posture. This probably represents an "accessory inspiratory" effect, which aids passive caudal diaphragmatic motion as the abdominal muscles relax at the onset of inspiration. Expiratory abdominal muscle activity was suppressed in phasic REM sleep, suggesting that loss of this "accessory inspiratory" effect may contribute to "central" hypopnoea. We conclude that, in patients with muscle weakness, nocturnal oxygenation correlates with diaphragmatic strength.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7656954

  9. Muscle metaboreceptor modulation of cutaneous active vasodilation

    NASA Technical Reports Server (NTRS)

    Crandall, C. G.; Stephens, D. P.; Johnson, J. M.

    1998-01-01

    PURPOSE: Isometric handgrip exercise in hyperthermia has been shown to reduce cutaneous vascular conductance (CVC) by inhibiting the cutaneous active vasodilator system. METHODS: To identify whether this response was initiated by muscle metaboreceptors, in seven subjects two 3-min bouts of isometric handgrip exercise in hyperthermia were performed, followed by 2 min of postexercise ischemia (PEI). An index of forearm skin blood flow (laser-Doppler flowmetry) was measured on the contralateral arm at an unblocked site and at a site at which adrenergic vasoconstrictor function was blocked via bretylium iontophoresis to reveal active cutaneous vasodilator function unambiguously. Sweat rate was measured via capacitance hygrometry, CVC was indexed from the ratio of skin blood flow to mean arterial pressure and was expressed as a percentage of maximal CVC at that site. In normothermia, neither isometric exercise nor PEI affected CVC (P > 0.05). RESULTS: The first bout of isometric handgrip exercise in hyperthermia reduced CVC at control sites and this reduction persisted through PEI (pre-exercise: 59.8 +/- 5.4, exercise: 49.8 +/- 4.9, PEI: 49.7 +/- 5.3% of maximum; both P < 0.05), whereas there were no significant changes in CVC at the bretylium treated sites. The succeeding bout of isometric exercise in hyperthermia significantly reduced CVC at both untreated (pre-exercise: 59.0 +/- 4.8, exercise: 47.3 +/- 4.0, PEI: 50.1 +/- 4.1% of maximum; both P < 0.05) and bretylium treated sites (pre-exercise: 61.4 +/- 7.3, exercise: 50.6 +/- 5.1, PEI: 53.9 +/- 6.0% of maximum, both P < 0.05). At both sites, CVC during PEI was lower than during the pre-exercise period (P < 0.05). Sweat rate rose significantly during both bouts of isometric exercise and remained elevated during PEI. CONCLUSIONS: These data suggest that the reduction in CVC during isometric exercise in hyperthermia, including the inhibition of the active vasodilator system, is primarily mediated by muscle

  10. Relative activity of respiratory muscles during prescribed inspiratory muscle training in healthy people

    PubMed Central

    Jung, Ju-hyeon; Kim, Nan-soo

    2016-01-01

    [Purpose] This study aimed to determine the effects of different intensities of inspiratory muscle training on the relative respiratory muscle activity in healthy adults. [Subjects and Methods] Thirteen healthy male volunteers were instructed to perform inspiratory muscle training (0%, 40%, 60%, and 80% maximal inspiratory pressure) on the basis of their individual intensities. The inspiratory muscle training was performed in random order of intensities. Surface electromyography data were collected from the right-side diaphragm, external intercostal, and sternocleidomastoid, and pulmonary functions (forced expiratory volume in 1 s, forced vital capacity, and their ratio; peak expiratory flow; and maximal inspiratory pressure) were measured. [Results] Comparison of the relative activity of the diaphragm showed significant differences between the 60% and 80% maximal inspiratory pressure intensities and baseline during inspiratory muscle training. Furthermore, significant differences were found in sternocleidomastoid relative activity between the 60% and 80% maximal inspiratory pressure intensities and baseline during inspiratory muscle training. [Conclusion] During inspiratory muscle training in the clinic, the patients were assisted (verbally or through feedback) by therapists to avoid overactivation of their accessory muscles (sternocleidomastoid). This study recommends that inspiratory muscle training be performed at an accurate and appropriate intensity through the practice of proper deep breathing. PMID:27134409

  11. Tumor Necrosis Factor Alpha Inhibits L-Type Ca2+ Channels in Sensitized Guinea Pig Airway Smooth Muscle through ERK 1/2 Pathway

    PubMed Central

    Reyes-García, Jorge; Flores-Soto, Edgar; Solís-Chagoyán, Héctor; Sommer, Bettina; Díaz-Hernández, Verónica; García-Hernández, Luz María

    2016-01-01

    Tumor necrosis factor alpha (TNF-α) is a potent proinflammatory cytokine that plays a significant role in the pathogenesis of asthma by inducing hyperresponsiveness and airway remodeling. TNF-α diminishes the L-type voltage dependent Ca2+ channel (L-VDCC) current in cardiac myocytes, an observation that seems paradoxical. In guinea pig sensitized tracheas KCl responses were lower than in control tissues. Serum from sensitized animals (Ser-S) induced the same phenomenon. In tracheal myocytes from nonsensitized (NS) and sensitized (S) guinea pigs, an L-VDCC current (ICa) was observed and diminished by Ser-S. The same decrease was detected in NS myocytes incubated with TNF-α, pointing out that this cytokine might be present in Ser-S. We observed that a small-molecule inhibitor of TNF-α (SMI-TNF) and a TNF-α receptor 1 (TNFR1) antagonist (WP9QY) reversed ICa decrease induced by Ser-S in NS myocytes, confirming the former hypothesis. U0126 (a blocker of ERK 1/2 kinase) also reverted the decrease in ICa. Neither cycloheximide (a protein synthesis inhibitor) nor actinomycin D (a transcription inhibitor) showed any effect on the TNF-α-induced ICa reduction. We found that CaV1.2 and CaV1.3 mRNA and proteins were expressed in tracheal myocytes and that sensitization did not modify them. In cardiac myocytes, ERK 1/2 phosphorylates two sites of the L-VDCC, augmenting or decreasing ICa; we postulate that, in guinea pig tracheal smooth muscle, TNF-α diminishes ICa probably by phosphorylating the L-VDCC site that reduces its activity through the ERK1/2 MAP kinase pathway. PMID:27445440

  12. Tumor Necrosis Factor Alpha Inhibits L-Type Ca(2+) Channels in Sensitized Guinea Pig Airway Smooth Muscle through ERK 1/2 Pathway.

    PubMed

    Reyes-García, Jorge; Flores-Soto, Edgar; Solís-Chagoyán, Héctor; Sommer, Bettina; Díaz-Hernández, Verónica; García-Hernández, Luz María; Montaño, Luis M

    2016-01-01

    Tumor necrosis factor alpha (TNF-α) is a potent proinflammatory cytokine that plays a significant role in the pathogenesis of asthma by inducing hyperresponsiveness and airway remodeling. TNF-α diminishes the L-type voltage dependent Ca(2+) channel (L-VDCC) current in cardiac myocytes, an observation that seems paradoxical. In guinea pig sensitized tracheas KCl responses were lower than in control tissues. Serum from sensitized animals (Ser-S) induced the same phenomenon. In tracheal myocytes from nonsensitized (NS) and sensitized (S) guinea pigs, an L-VDCC current (ICa) was observed and diminished by Ser-S. The same decrease was detected in NS myocytes incubated with TNF-α, pointing out that this cytokine might be present in Ser-S. We observed that a small-molecule inhibitor of TNF-α (SMI-TNF) and a TNF-α receptor 1 (TNFR1) antagonist (WP9QY) reversed ICa decrease induced by Ser-S in NS myocytes, confirming the former hypothesis. U0126 (a blocker of ERK 1/2 kinase) also reverted the decrease in ICa. Neither cycloheximide (a protein synthesis inhibitor) nor actinomycin D (a transcription inhibitor) showed any effect on the TNF-α-induced ICa reduction. We found that CaV1.2 and CaV1.3 mRNA and proteins were expressed in tracheal myocytes and that sensitization did not modify them. In cardiac myocytes, ERK 1/2 phosphorylates two sites of the L-VDCC, augmenting or decreasing ICa; we postulate that, in guinea pig tracheal smooth muscle, TNF-α diminishes ICa probably by phosphorylating the L-VDCC site that reduces its activity through the ERK1/2 MAP kinase pathway. PMID:27445440

  13. Azithromycin has a direct relaxant effect on precontracted airway smooth muscle.

    PubMed

    Daenas, Christos; Hatziefthimiou, Apostolia A; Gourgoulianis, Konstantinos I; Molyvdas, Paschalis Adam

    2006-12-28

    Macrolides have been proven to have beneficial bacteriostatic and anti-inflammatory properties, but very little is known about the potential value of their bronchodilatory effect. Therefore, in the present study we investigated the effect of azithromycin on contractile responses of isolated rabbit tracheal strips to carbachol or KCl. Azithromycin has a relaxant, concentration-dependent effect on tracheal strips precontracted with carbachol (300 nM), significant from the concentration of 1 muM. The mechanical removal of epithelium did not alter the effect of azithromycin. Azithromycin (100 microM) also relaxed tracheal strips precontracted with KCl (80 mM) even in the presence of atropine (100 microM). Moreover, azithromycin (100 microM) decreased contractions induced by 300 nM and 10 microM carbachol to 55.4% and 80.5% of initial contraction, respectively. The relaxant effect of azithromycin persisted in both calcium free solution and in the presence of the calcium channel antagonist, verapamil. The relaxant effect of azithromycin was not altered by the pre-treatment of preparations with the inhibitors of Ca(2+)-ATPase (cyclopiazonic acid), Na(+)-K(+) ATPase (ouabain), Rho-associated kinase [(R)-(+)-trans-4-(1-aminoethyl)-N-(4-pyridyl)cyclohexanecarboxamide dihydrochloride] (Y-27632) or the non-specific cAMP and cGMP phosphodiesterases inhibitor 3-isobutyl-1-methyl-2,6(1H,3H)-purinedione (IBMX). These results suggest that azithromycin has a concentration-dependent, epithelium-independent, direct relaxant effect on precontracted tracheal strips that is not mediated via inhibition of Ca(2+) influx or Ca(2+) release from intracellular stores. Also, it is not due to alteration of the function of Na(+)-K(+) ATPase and does not depend on the formation of cAMP/cGMP or the Rho/Rho-activated kinase pathway. PMID:17070799

  14. Effect of experimental muscle pain on maximal voluntary activation of human biceps brachii muscle.

    PubMed

    Khan, Serajul I; McNeil, Chris J; Gandevia, Simon C; Taylor, Janet L

    2011-09-01

    Muscle pain has widespread effects on motor performance, but the effect of pain on voluntary activation, which is the level of neural drive to contracting muscle, is not known. To determine whether induced muscle pain reduces voluntary activation during maximal voluntary contractions, voluntary activation of elbow flexors was assessed with both motor-point stimulation and transcranial magnetic stimulation over the motor cortex. In addition, we performed a psychophysical experiment to investigate the effect of induced muscle pain across a wide range of submaximal efforts (5-75% maximum). In all studies, elbow flexion torque was recorded before, during, and after experimental muscle pain by injection of 1 ml of 5% hypertonic saline into biceps. Injection of hypertonic saline evoked deep pain in the muscle (pain rating ∼5 on a scale from 0 to 10). Experimental muscle pain caused a small (∼5%) but significant reduction of maximal voluntary torque in the motor-point and motor cortical studies (P < 0.001 and P = 0.045, respectively; n = 7). By contrast, experimental muscle pain had no significant effect on voluntary activation when assessed with motor-point and motor cortical stimulation although voluntary activation tested with motor-point stimulation was reduced by ∼2% in contractions after pain had resolved (P = 0.003). Furthermore, induced muscle pain had no significant effect on torque output during submaximal efforts (P > 0.05; n = 6), which suggests that muscle pain did not alter the relationship between the sense of effort and production of voluntary torque. Hence, the present study suggests that transient experimental muscle pain in biceps brachii has a limited effect on central motor pathways. PMID:21737829

  15. Muscle Activation Patterns When Passively Stretching Spastic Lower Limb Muscles of Children with Cerebral Palsy

    PubMed Central

    Bar-On, Lynn; Aertbeliën, Erwin; Molenaers, Guy; Desloovere, Kaat

    2014-01-01

    The definition of spasticity as a velocity-dependent activation of the tonic stretch reflex during a stretch to a passive muscle is the most widely accepted. However, other mechanisms are also thought to contribute to pathological muscle activity and, in patients post-stroke and spinal cord injury can result in different activation patterns. In the lower-limbs of children with spastic cerebral palsy (CP) these distinct activation patterns have not yet been thoroughly explored. The aim of the study was to apply an instrumented assessment to quantify different muscle activation patterns in four lower-limb muscles of children with CP. Fifty-four children with CP were included (males/females n = 35/19; 10.8±3.8 yrs; bilateral/unilateral involvement n =  32/22; Gross Motor Functional Classification Score I–IV) of whom ten were retested to evaluate intra-rater reliability. With the subject relaxed, single-joint, sagittal-plane movements of the hip, knee, and ankle were performed to stretch the lower-limb muscles at three increasing velocities. Muscle activity and joint motion were synchronously recorded using inertial sensors and electromyography (EMG) from the adductors, medial hamstrings, rectus femoris, and gastrocnemius. Muscles were visually categorised into activation patterns using average, normalized root mean square EMG (RMS-EMG) compared across increasing position zones and velocities. Based on the visual categorisation, quantitative parameters were defined using stretch-reflex thresholds and normalized RMS-EMG. These parameters were compared between muscles with different activation patterns. All patterns were dominated by high velocity-dependent muscle activation, but in more than half, low velocity-dependent activation was also observed. Muscle activation patterns were found to be both muscle- and subject-specific (p<0.01). The intra-rater reliability of all quantitative parameters was moderate to good. Comparing RMS-EMG between incremental

  16. a Dynamical Model of Muscle Activation, Fatigue and Recovery

    NASA Astrophysics Data System (ADS)

    Liu, Jing Z.; Yue, Guang H.; Brown, Robert W.

    2001-04-01

    A dynamical model on muscle activation, fatigue, and recovery was developed to provide a theoretical framework for explaining the force produced by muscle(s) during the process of getting activated and fatigued. By simplifying the fatigue effect and the recovery effect as two phenomenological parameters (F, R), we developed a set of dynamical equations to describe the behavior of muscle(s) as a group of motor units under an external drive, e.g., voluntary brain effort. This model provides a macroscopic view for understanding the biophysical mechanisms of voluntary drive, fatigue effect, and recovery in stimulating, limiting and modulating the force output from muscle(s). Agreement between the experimental data and the predicted forces is excellent. This model may also generate new possibilities in clinical and engineering applications. The parameters introduced by this model can serve as good indicators of physical conditions, and may be useful for quantitative diagnosis of certain diseases related to muscles, especially symptoms of fatigue. Inference from the model can clarify a long-debating question regarding the maximal possibility of muscle force production. It can also be used as guideline for simulating real muscle in muscle engineering or design of human-mimic robot.

  17. Neck muscle activity in skydivers during parachute opening shock.

    PubMed

    Lo Martire, R; Gladh, K; Westman, A; Lindholm, P; Nilsson, J; Äng, B O

    2016-03-01

    This observational study investigated skydiver neck muscle activity during parachute opening shock (POS), as epidemiological data recently suggested neck pain in skydivers to be related to POS. Twenty experienced skydivers performed two terminal velocity skydives each. Surface electromyography quantified muscle activity bilaterally from the anterior neck, the upper and lower posterior neck, and the upper shoulders; and two triaxial accelerometers sampled deceleration. Muscle activity was normalized as the percentage of reference maximum voluntary electrical activity (% MVE); and temporal muscle activity onset was related to POS onset. Our results showed that neck muscle activity during POS reached mean magnitudes of 53-104% MVE, often exceeding reference activity in the lower posterior neck and upper shoulders. All investigated muscle areas' mean temporal onsets occurred <50 ms after POS onset (9-34 ms latencies), which is consistent with anticipatory motor control. The high muscle activity observed supports that the neck is under substantial strain during POS, while temporal muscle activation suggests anticipatory motor control to be a strategy used by skydivers to protect the cervical spine from POS. This study's findings contribute to understanding the high rates of POS-related neck pain, and further support the need for evaluation of neck pain preventative strategies. PMID:25754941

  18. Seasonal variation in muscle sympathetic nerve activity.

    PubMed

    Cui, Jian; Muller, Matthew D; Blaha, Cheryl; Kunselman, Allen R; Sinoway, Lawrence I

    2015-08-01

    Epidemiologic data suggest there are seasonal variations in the incidence of severe cardiac events with peak levels being evident in the winter. Whether autonomic indices including muscle sympathetic nerve activity (MSNA) vary with season remains unclear. In this report, we tested the hypothesis that resting MSNA varies with the seasons of the year with peak levels evident in the winter. We analyzed the supine resting MSNA in 60 healthy subjects. Each subject was studied during two, three, or four seasons (total 237 visits). MSNA burst rate in the winter (21.0 ± 6.8 burst/min, mean ± SD) was significantly greater than in the summer (13.5 ± 5.8 burst/min, P < 0.001), the spring (17.1 ± 9.0 burst/min, P = 0.03), and the fall (17.9 ± 7.7 burst/min, P = 0.002). There was no significant difference in MSNA for other seasonal comparisons. The results suggest that resting sympathetic nerve activity varies along the seasons, with peak levels evident in the winter. We speculate that the seasonal changes in sympathetic activity may be a contribution to the previously observed seasonal variations in cardiovascular morbidity and mortality. PMID:26265752

  19. Seasonal variation in muscle sympathetic nerve activity

    PubMed Central

    Cui, Jian; Muller, Matthew D; Blaha, Cheryl; Kunselman, Allen R; Sinoway, Lawrence I

    2015-01-01

    Epidemiologic data suggest there are seasonal variations in the incidence of severe cardiac events with peak levels being evident in the winter. Whether autonomic indices including muscle sympathetic nerve activity (MSNA) vary with season remains unclear. In this report, we tested the hypothesis that resting MSNA varies with the seasons of the year with peak levels evident in the winter. We analyzed the supine resting MSNA in 60 healthy subjects. Each subject was studied during two, three, or four seasons (total 237 visits). MSNA burst rate in the winter (21.0 ± 6.8 burst/min, mean ± SD) was significantly greater than in the summer (13.5 ± 5.8 burst/min, P < 0.001), the spring (17.1 ± 9.0 burst/min, P = 0.03), and the fall (17.9 ± 7.7 burst/min, P = 0.002). There was no significant difference in MSNA for other seasonal comparisons. The results suggest that resting sympathetic nerve activity varies along the seasons, with peak levels evident in the winter. We speculate that the seasonal changes in sympathetic activity may be a contribution to the previously observed seasonal variations in cardiovascular morbidity and mortality. PMID:26265752

  20. Force enhancement and force depression in a modified muscle model used for muscle activation prediction.

    PubMed

    Kosterina, Natalia; Wang, Ruoli; Eriksson, Anders; Gutierrez-Farewik, Elena M

    2013-08-01

    This article introduces history-dependent effects in a skeletal muscle model applied to dynamic simulations of musculoskeletal system motion. Force depression and force enhancement induced by active muscle shortening and lengthening, respectively, represent muscle history effects. A muscle model depending on the preceding contractile events together with the current parameters was developed for OpenSim software, and applied in simulations of standing heel-raise and squat movements. Muscle activations were computed using joint kinematics and ground reaction forces recorded from the motion capture of seven individuals. In the muscle-actuated simulations, a modification was applied to the computed activation, and was compared to the measured electromyography data. For the studied movements, the history gives a small but visible effect to the muscular force trace, but some parameter values must be identified before the exact magnitude can be analysed. The muscle model modification improves the existing muscle models and gives a more accurate description of underlying forces and activations in musculoskeletal system movement simulations. PMID:23561824

  1. PPARδ expression is influenced by muscle activity and induces slow muscle properties in adult rat muscles after somatic gene transfer

    PubMed Central

    Lunde, Ida G; Ekmark, Merete; Rana, Zaheer A; Buonanno, Andres; Gundersen, Kristian

    2007-01-01

    The effects of exercise on skeletal muscle are mediated by a coupling between muscle electrical activity and gene expression. Several activity correlates, such as intracellular Ca2+, hypoxia and metabolites like free fatty acids (FFAs), might initiate signalling pathways regulating fibre-type-specific genes. FFAs can be sensed by lipid-dependent transcription factors of the peroxisome proliferator-activated receptor (PPAR) family. We found that the mRNA for the predominant muscle isoform, PPARδ, was three-fold higher in the slow/oxidative soleus compared to the fast/glycolytic extensor digitorum longus (EDL) muscle. In histological sections of the soleus, the most oxidative fibres display the highest levels of PPARδ protein. When the soleus muscle was stimulated electrically by a pattern mimicking fast/glycolytic IIb motor units, the mRNA level of PPARδ was reduced to less than half within 24 h. In the EDL, a three-fold increase was observed after slow type I-like electrical stimulation. When a constitutively active form of PPARδ was overexpressed for 14 days in normally active adult fibres after somatic gene transfer, the number of I/IIa hybrids in the EDL more than tripled, IIa fibres increased from 14% to 25%, and IIb fibres decreased from 55% to 45%. The level of succinate dehydrogenase activity increased and size decreased, also when compared to normal fibres of the same type. Thus PPARδ can change myosin heavy chain, oxidative enzymes and size locally in muscle cells in the absence of general exercise. Previous studies on PPARδ in muscle have been performed in transgenic animals where the transgene has been present during muscle development. Our data suggest that PPARδ can mediate activity effects acutely in pre-existing adult fibres, and thus is an important link in excitation–transcription coupling. PMID:17463039

  2. Effects of 12 Months Continuous Positive Airway Pressure on Sympathetic Activity Related Brainstem Function and Structure in Obstructive Sleep Apnea.

    PubMed

    Henderson, Luke A; Fatouleh, Rania H; Lundblad, Linda C; McKenzie, David K; Macefield, Vaughan G

    2016-01-01

    Muscle sympathetic nerve activity (MSNA) is greatly elevated in patients with obstructive sleep apnea (OSA) during normoxic daytime wakefulness. Increased MSNA is a precursor to hypertension and elevated cardiovascular morbidity and mortality. However, the mechanisms underlying the high MSNA in OSA are not well understood. In this study we used concurrent microneurography and magnetic resonance imaging to explore MSNA-related brainstem activity changes and anatomical changes in 15 control and 15 OSA subjects before and after 6 and 12 months of continuous positive airway pressure (CPAP) treatment. We found that following 6 and 12 months of CPAP treatment, resting MSNA levels were significantly reduced in individuals with OSA. Furthermore, this MSNA reduction was associated with restoration of MSNA-related brainstem activity and structural changes in the medullary raphe, rostral ventrolateral medulla, dorsolateral pons, and ventral midbrain. This restoration occurred after 6 months of CPAP treatment and was maintained following 12 months CPAP. These findings show that continual CPAP treatment is an effective long-term treatment for elevated MSNA likely due to its effects on restoring brainstem structure and function. PMID:27013952

  3. Effects of 12 Months Continuous Positive Airway Pressure on Sympathetic Activity Related Brainstem Function and Structure in Obstructive Sleep Apnea

    PubMed Central

    Henderson, Luke A.; Fatouleh, Rania H.; Lundblad, Linda C.; McKenzie, David K.; Macefield, Vaughan G.

    2016-01-01

    Muscle sympathetic nerve activity (MSNA) is greatly elevated in patients with obstructive sleep apnea (OSA) during normoxic daytime wakefulness. Increased MSNA is a precursor to hypertension and elevated cardiovascular morbidity and mortality. However, the mechanisms underlying the high MSNA in OSA are not well understood. In this study we used concurrent microneurography and magnetic resonance imaging to explore MSNA-related brainstem activity changes and anatomical changes in 15 control and 15 OSA subjects before and after 6 and 12 months of continuous positive airway pressure (CPAP) treatment. We found that following 6 and 12 months of CPAP treatment, resting MSNA levels were significantly reduced in individuals with OSA. Furthermore, this MSNA reduction was associated with restoration of MSNA-related brainstem activity and structural changes in the medullary raphe, rostral ventrolateral medulla, dorsolateral pons, and ventral midbrain. This restoration occurred after 6 months of CPAP treatment and was maintained following 12 months CPAP. These findings show that continual CPAP treatment is an effective long-term treatment for elevated MSNA likely due to its effects on restoring brainstem structure and function. PMID:27013952

  4. Activation of an apical Cl- conductance by Ca2+ ionophores in cystic fibrosis airway epithelia.

    PubMed

    Willumsen, N J; Boucher, R C

    1989-02-01

    Cystic fibrosis (CF) airway epithelia express a defect in adenosine 3',5'-cyclic monophosphate (cAMP)-dependent regulation of apical membrane Cl- channels. Recent patch-clamp studies have raised the possibility that Ca2+ -dependent mechanisms for the activation of Cl- secretion may be preserved in CF airway epithelia. To determine 1) whether intact normal (N1) and CF airway epithelia exhibit a Ca2+ -dependent mechanism for activation of Cl- secretion and 2) whether Ca2+ -dependent mechanism for activation of Cl- secretion and 2) whether Ca2+ -dependent mechanisms initiate Cl- secretion via activation of an apical membrane Cl- conductance (GCl-), nasal epithelia from N1 and CF subjects were cultured on collagen membranes, and responses to isoproterenol or Ca2- ionophores [A23187 10(-6) M; ionomycin (10(-5)M)] were measured with transepithelial and intracellular techniques. Isoproterenol induced activation of an apical membrane GCl- in N1 cultures but was ineffective in CF. In contrast, in both N1 and CF amiloride-pretreated cultures, A23187 induced an increase in the equivalent short-circuit current that was associated with an activation of an apical membrane Gc1- and was bumetanide inhibitable. A23187 addition during superfusion of the lumen with a low Cl- (3 mM) solution reduced intracellular Cl- activity of CF cells. A Ca2+ ionophore of different selectivity properties, ionomycin, was also an effective Cl- secretagogue in both N1 and CF cultures. We conclude that 1) the A23187 induced Cl- secretion via activation of an apical GCl- in N1 human nasal epithelium, and 2) in contrast to an isoproterenol-dependent path, a Ca2+ -dependent path for GCl- activation is preserved in CF epithelia. PMID:2465689

  5. Estimates of activation in arterial smooth muscle.

    PubMed

    Singer, H A; Kamm, K E; Murphy, R A

    1986-09-01

    We have previously described the onset of a "latch" state in the swine carotid media after K+ depolarization. This state was characterized by maintained stress after a decrease in shortening velocities and in the level of cross-bridge phosphorylation. The present experiments were designed to determine whether there were changes in other mechanical properties in swine carotid media associated with the onset of the latch state. Medial strips (less than 500 microM thick), incubated in physiological salt solution (PSS) at 37 degrees C at their optimal length (Lo), were subjected to ramp stretches (5.86 mm/s) of 5% Lo. The active stress (Sa) response to stretch was computed by subtraction of the passive element contribution (as determined from identical stretches after 30 min incubation in Ca2+-free PSS) from the total response in the activated muscle. Transitions in the total and active stress responses to stretch were observed in strips stimulated with 109 mM K+ for 1 min or longer and were interpreted as yielding of the contractile apparatus. Active dynamic stiffness (dS/dLo) calculated from the initial 1% Lo portion of the stretch response, correlated linearly with active stress over a wide range. Maximal stress and dynamic stiffness were reached by 1 min and were maintained for at least 30 min in K+-depolarized preparations. However, yield stress increased significantly between 1 and 10 min, and there was a large increase in the length at which yield was observed (1.09 +/- 0.06 to 1.86 +/- 0.10% Lo; n = 9). These increases were maintained between 10 and 30 min.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3752237

  6. Chronic Low Dose Chlorine Exposure Aggravates Allergic Inflammation and Airway Hyperresponsiveness and Activates Inflammasome Pathway

    PubMed Central

    Kim, Sae-Hoon; Park, Da-Eun; Lee, Hyun-Seung; Kang, Hye-Ryun; Cho, Sang-Heon

    2014-01-01

    Background Epidemiologic clinical studies suggested that chronic exposure to chlorine products is associated with development of asthma and aggravation of asthmatic symptoms. However, its underlying mechanism was not clearly understood. Studies were undertaken to define the effects and mechanisms of chronic low-dose chlorine exposure in the pathogenesis of airway inflammation and airway hyperresponsiveness (AHR). Methods Six week-old female BALB/c mice were sensitized and challenged with OVA in the presence and absence of chronic low dose chlorine exposure of naturally vaporized gas of 5% sodium hypochlorite solution. Airway inflammation and AHR were evaluated by bronchoalveolar lavage (BAL) cell recovery and non-invasive phlethysmography, respectively. Real-time qPCR, Western blot assay, and ELISA were used to evaluate the mRNA and protein expressions of cytokines and other inflammatory mediators. Human A549 and murine epithelial (A549 and MLE12) and macrophage (AMJ2-C11) cells were used to define the responses to low dose chlorine exposure in vitro. Results Chronic low dose chlorine exposure significantly augmented airway inflammation and AHR in OVA-sensitized and challenged mice. The expression of Th2 cytokines IL-4 and IL-5 and proinflammatory cytokine IL-1β and IL-33 were significantly increased in OVA/Cl group compared with OVA group. The chlorine exposure also activates the major molecules associated with inflammasome pathway in the macrophages with increased expression of epithelial alarmins IL-33 and TSLP in vitro. Conclusion Chronic low dose exposure of chlorine aggravates allergic Th2 inflammation and AHR potentially through activation of inflammasome danger signaling pathways. PMID:25202911

  7. Electrical activation of artificial muscles containing polyacrylonitrile gel fibers.

    PubMed

    Schreyer, H B; Gebhart, N; Kim, K J; Shahinpoor, M

    2000-01-01

    Gel fibers made from polyacrylonitrile (PAN) are known to elongate and contract when immersed in caustic and acidic solutions, respectively. The amount of contraction for these pH-activated fibers is 50% or greater, and the strength of these fibers is shown to be comparable to that of human muscle. Despite these attributes, the need of strong acids and bases for actuation has limited the use of PAN gel fibers as linear actuators or artificial muscles. Increasing the conductivity by depositing platinum on the fibers or combining the fibers with graphite fibers has allowed for electrical activation of artificial muscles containing gel fibers when placed in an electrochemical cell. The electrolysis of water in such a cell produces hydrogen ions at an artificial muscle anode, thus locally decreasing the pH and causing the muscle to contract. Reversing the electric field allows the PAN muscle to elongate. A greater than 40% contraction in artificial muscle length in less than 10 min is observed when it is placed as an electrode in a 10 mM NaCl electrolyte solution and connected to a 10 V power supply. These results indicate potential in developing electrically activated PAN muscles and linear actuators, which would be much more applicable than chemically activated muscles. PMID:11710194

  8. Independent Active Contraction of Extraocular Muscle Compartments

    PubMed Central

    Shin, Andrew; Yoo, Lawrence; Demer, Joseph L.

    2015-01-01

    Purpose. Intramuscular innervation of horizontal rectus extraocular muscle (EOMs) is segregated into superior and inferior (transverse) compartments, whereas all EOMs are also divided into global (GL) and orbital (OL) layers with scleral and pulley insertions, respectively. Mechanical independence between both types of compartments has been demonstrated during passive tensile loading. We examined coupling between EOM compartments during active, ex vivo contraction. Methods. Fresh bovine EOMs were removed, and one compartment of each was coated with hydrophobic petrolatum. Contraction of the uncoated compartment was induced by immersion in a solution of 50 mM CaCl2 at 38°C labeled with sodium fluorescein dye, whereas tensions in both compartments were monitored by strain gauges. Control experiments omitted petrolatum so that the entire EOM contracted. After physiological experiments, EOMs were sectioned transversely to demonstrate specificity of CaCl2 permeation by yellow fluorescence dye excited by blue light. Results. In control experiments without petrolatum, both transverse and GL and OL compartments contracted similarly. Selective compartmental omission of petrolatum caused markedly independent compartmental contraction whether measured at the GL or the OL insertions or for transverse compartments at the scleral insertion. Although some CaCl2 spread occurred, mean (±SD) tension in the coated compartments averaged only 10.5 ± 3.3% and 6.0 ± 1.5% in GL/OL and transverse compartments, respectively relative to uncoated compartments. Fluorescein penetration confirmed selective CaCl2 permeation. Conclusions. These data confirm passive tensile findings of mechanical independence of EOM compartments and extend results to active contraction. EOMs behave actively as if composed of mechanically independent parallel fiber bundles having different insertional targets, consistent with the active pulley and transverse compartmental hypotheses. PMID:25503460

  9. Locomotor activity influences muscle architecture and bone growth but not muscle attachment site morphology

    PubMed Central

    Rabey, Karyne N.; Green, David J.; Taylor, Andrea B.; Begun, David R.; Richmond, Brian G.; McFarlin, Shannon C.

    2014-01-01

    The ability to make behavioural inferences from skeletal remains is critical to understanding the lifestyles and activities of past human populations and extinct animals. Muscle attachment site (enthesis) morphology has long been assumed to reflect muscle strength and activity during life, but little experimental evidence exists to directly link activity patterns with muscle development and the morphology of their attachments to the skeleton. We used a mouse model to experimentally test how the level and type of activity influences forelimb muscle architecture of spinodeltoideus, acromiodeltoideus, and superficial pectoralis, bone growth rate and gross morphology of their insertion sites. Over an 11-week period, we collected data on activity levels in one control group and two experimental activity groups (running, climbing) of female wild-type mice. Our results show that both activity type and level increased bone growth rates influenced muscle architecture, including differences in potential muscular excursion (fibre length) and potential force production (physiological cross-sectional area). However, despite significant influences on muscle architecture and bone development, activity had no observable effect on enthesis morphology. These results suggest that the gross morphology of entheses is less reliable than internal bone structure for making inferences about an individual’s past behaviour. PMID:25467113

  10. Muscle Transcriptional Profile Based on Muscle Fiber, Mitochondrial Respiratory Activity, and Metabolic Enzymes

    PubMed Central

    Liu, Xuan; Du, Yang; Trakooljul, Nares; Brand, Bodo; Muráni, Eduard; Krischek, Carsten; Wicke, Michael; Schwerin, Manfred; Wimmers, Klaus; Ponsuksili, Siriluck

    2015-01-01

    Skeletal muscle is a highly metabolically active tissue that both stores and consumes energy. Important biological pathways that affect energy metabolism and metabolic fiber type in muscle cells may be identified through transcriptomic profiling of the muscle, especially ante mortem. Here, gene expression was investigated in malignant hyperthermia syndrome (MHS)-negative Duroc and Pietrian (PiNN) pigs significantly differing for the muscle fiber types slow-twitch-oxidative fiber (STO) and fast-twitch-oxidative fiber (FTO) as well as mitochondrial activity (succinate-dependent state 3 respiration rate). Longissimus muscle samples were obtained 24 h before slaughter and profiled using cDNA microarrays. Differential gene expression between Duroc and PiNN muscle samples were associated with protein ubiquitination, stem cell pluripotency, amyloid processing, and 3-phosphoinositide biosynthesis and degradation pathways. In addition, weighted gene co-expression network analysis within both breeds identified several co-expression modules that were associated with the proportion of different fiber types, mitochondrial respiratory activity, and ATP metabolism. In particular, Duroc results revealed strong correlations between mitochondrion-associated co-expression modules and STO (r = 0.78), fast-twitch glycolytic fiber (r = -0.98), complex I (r=0.72) and COX activity (r = 0.86). Other pathways in the protein-kinase-activity enriched module were positively correlated with STO (r=0.93), while negatively correlated with FTO (r = -0.72). In contrast to PiNN, co-expression modules enriched in macromolecule catabolic process, actin cytoskeleton, and transcription activator activity were associated with fiber types, mitochondrial respiratory activity, and metabolic enzyme activities. Our results highlight the importance of mitochondria for the oxidative capacity of porcine muscle and for breed-dependent molecular pathways in muscle cell fibers. PMID:26681915

  11. A three-dimensional muscle activity imaging technique for assessing pelvic muscle function

    NASA Astrophysics Data System (ADS)

    Zhang, Yingchun; Wang, Dan; Timm, Gerald W.

    2010-11-01

    A novel multi-channel surface electromyography (EMG)-based three-dimensional muscle activity imaging (MAI) technique has been developed by combining the bioelectrical source reconstruction approach and subject-specific finite element modeling approach. Internal muscle activities are modeled by a current density distribution and estimated from the intra-vaginal surface EMG signals with the aid of a weighted minimum norm estimation algorithm. The MAI technique was employed to minimally invasively reconstruct electrical activity in the pelvic floor muscles and urethral sphincter from multi-channel intra-vaginal surface EMG recordings. A series of computer simulations were conducted to evaluate the performance of the present MAI technique. With appropriate numerical modeling and inverse estimation techniques, we have demonstrated the capability of the MAI technique to accurately reconstruct internal muscle activities from surface EMG recordings. This MAI technique combined with traditional EMG signal analysis techniques is being used to study etiologic factors associated with stress urinary incontinence in women by correlating functional status of muscles characterized from the intra-vaginal surface EMG measurements with the specific pelvic muscle groups that generated these signals. The developed MAI technique described herein holds promise for eliminating the need to place needle electrodes into muscles to obtain accurate EMG recordings in some clinical applications.

  12. Viscoelastic and dynamic nonlinear properties of airway smooth muscle tissue: roles of mechanical force and the cytoskeleton.

    PubMed

    Ito, Satoru; Majumdar, Arnab; Kume, Hiroaki; Shimokata, Kaoru; Naruse, Keiji; Lutchen, Kenneth R; Stamenovic, Dimitrije; Suki, Béla

    2006-06-01

    The viscoelastic and dynamic nonlinear properties of guinea pig tracheal smooth muscle tissues were investigated by measuring the storage (G') and loss (G") moduli using pseudorandom small-amplitude length oscillations between 0.12 and 3.5 Hz superimposed on static strains of either 10 or 20% of initial length. The G" and G' spectra were interpreted using a linear viscoelastic model incorporating damping (G) and stiffness (H), respectively. Both G and H were elevated following an increase in strain from 10 to 20%. There was no change in harmonic distortion (K(d)), an index of dynamic nonlinearity, between 10 and 20% strains. Application of methacholine at 10% strain significantly increased G and H while it decreased K(d). Cytochalasin D, isoproterenol, and HA-1077, a Rho-kinase inhibitor, significantly decreased both G and H but increased K(d). Following cytochalasin D, G, H, and K(d) were all elevated when mean strain increased from 10 to 20%. There were no changes in hysteresivity, G/H, under any condition. We conclude that not all aspects of the viscoelastic properties of tracheal smooth muscle strips are similar to those previously observed in cultured cells. We attribute these differences to the contribution of the extracellular matrix. Additionally, using a network model, we show that the dynamic nonlinear behavior, which has not been observed in cell culture, is associated with the state of the contractile stress and may derive from active polymerization within the cytoskeleton. PMID:16414980

  13. Tissue Plasminogen Activator Prevents Mortality from Sulfur Mustard Analog–Induced Airway Obstruction

    PubMed Central

    Hendry-Hofer, Tara B.; Loader, Joan E.; Rioux, Jacqueline S.; Garlick, Rhonda B.; White, Carl W.

    2013-01-01

    Sulfur mustard (SM) inhalation causes the rare but life-threatening disorder of plastic bronchitis, characterized by bronchial cast formation, resulting in severe airway obstruction that can lead to respiratory failure and death. Mortality in those requiring intubation is greater than 80%. To date, no antidote exists for SM toxicity. In addition, therapies for plastic bronchitis are solely anecdotal, due to lack of systematic research available to assess drug efficacy in improving mortality and/or morbidity. Adult rats exposed to SM analog were treated with intratracheal tissue plasminogen activator (tPA) (0.15–0.7 mg/kg, 5.5 and 6.5 h), compared with controls (no treatment, isoflurane, and placebo). Respiratory distress and pulse oximetry were assessed (for 12 or 48 h), and arterial blood gases were obtained at study termination (12 h). Microdissection of fixed lungs was done to assess airway obstruction by casts. Optimal intratracheal tPA treatment (0.7 mg/kg) completely eliminated mortality (0% at 48 h), and greatly improved morbidity in this nearly uniformly fatal disease model (90–100% mortality at 48 h). tPA normalized plastic bronchitis–associated hypoxemia, hypercarbia, and lactic acidosis, and improved respiratory distress (i.e., clinical scores) while decreasing airway fibrin casts. Intratracheal tPA diminished airway-obstructive fibrin–containing casts while improving clinical respiratory distress, pulmonary gas exchange, tissue oxygenation, and oxygen utilization in our model of severe chemically induced plastic bronchitis. Most importantly, mortality, which was associated with hypoxemia and clinical respiratory distress, was eliminated. PMID:23258228

  14. Effect of Expiratory Resistive Loading in Expiratory Muscle Strength Training on Orbicularis Oris Muscle Activity

    PubMed Central

    Yanagisawa, Yukio; Matsuo, Yoshimi; Shuntoh, Hisato; Horiuchi, Noriaki

    2014-01-01

    [Purpose] The purpose of this study was to elucidate the effect of expiratory resistive loading on orbicularis oris muscle activity. [Subjects] Subjects were 23 healthy individuals (11 males, mean age 25.5±4.3 years; 12 females, mean age 25.0±3.0 years). [Methods] Surface electromyography was performed to measure the activity of the orbicularis oris muscle during maximum lip closure and resistive loading at different expiratory pressures. Measurement was performed at 10%, 30%, 50%, and 100% of maximum expiratory pressure (MEP) for all subjects. The t-test was used to compare muscle activity between maximum lip closure and 100% MEP, and analysis of variance followed by multiple comparisons was used to compare the muscle activities observed at different expiratory pressures. [Results] No significant difference in muscle activity was observed between maximum lip closure and 100% MEP. Analysis of variance with multiple comparisons revealed significant differences among the different expiratory pressures. [Conclusion] Orbicularis oris muscle activity increased with increasing expiratory resistive loading. PMID:24648644

  15. Influence of different control strategies on muscle activation patterns in trunk muscles

    PubMed Central

    Hansen, Laura; Anders, Christoph

    2014-01-01

    Abstract Adequate training of the trunk muscles is essential to prevent low back pain. Although sit‐ups are simple to perform, the perceived high effort is the reason why training the abdominal muscles is seldom continued over a longer period of time. It is well known that the abdominal muscles are inferior to the back muscles in terms of force, but this cannot explain the extreme difference in perceived effort between trunk flexion and extension tasks. Therefore, this study was aimed at the identification of control strategy influences on the muscular stress level. Thirty‐nine subjects were investigated. The performed tasks were restricted to the sagittal plane and were implemented with simulated and realized tilt angles. Subjects were investigated in an upright position with their lower bodies fixed and their upper bodies free. Posture‐controlled tasks involved graded forward and backward tilting, while force‐controlled tasks involved the application of force based on a virtual tilt angle. The Surface EMG (SEMG) was taken from five trunk muscles on both sides. Control strategies seemed to have no systematic influence on the SEMG amplitudes of the back muscles. In contrast, the abdominal muscles exhibited significantly higher stress levels under posture‐controlled conditions without relevantly increasing antagonistic co‐activation of back muscles. The abdominal muscles' relative differences ranged from an average of 20% for the external oblique abdominal muscle to approximately 40% for the rectus abdominal muscle. The perceived high effort expended during sit‐ups can now be explained by the posture‐controlled contractions that are required. PMID:25501425

  16. Muscle Activation during Gait in Children with Duchenne Muscular Dystrophy.

    PubMed

    Ropars, Juliette; Lempereur, Mathieu; Vuillerot, Carole; Tiffreau, Vincent; Peudenier, Sylviane; Cuisset, Jean-Marie; Pereon, Yann; Leboeuf, Fabien; Delporte, Ludovic; Delpierre, Yannick; Gross, Raphaël; Brochard, Sylvain

    2016-01-01

    The aim of this prospective study was to investigate changes in muscle activity during gait in children with Duchenne muscular Dystrophy (DMD). Dynamic surface electromyography recordings (EMGs) of 16 children with DMD and pathological gait were compared with those of 15 control children. The activity of the rectus femoris (RF), vastus lateralis (VL), medial hamstrings (HS), tibialis anterior (TA) and gastrocnemius soleus (GAS) muscles was recorded and analysed quantitatively and qualitatively. The overall muscle activity in the children with DMD was significantly different from that of the control group. Percentage activation amplitudes of RF, HS and TA were greater throughout the gait cycle in the children with DMD and the timing of GAS activity differed from the control children. Significantly greater muscle coactivation was found in the children with DMD. There were no significant differences between sides. Since the motor command is normal in DMD, the hyper-activity and co-contractions likely compensate for gait instability and muscle weakness, however may have negative consequences on the muscles and may increase the energy cost of gait. Simple rehabilitative strategies such as targeted physical therapies may improve stability and thus the pattern of muscle activity. PMID:27622734

  17. Decoding upper limb residual muscle activity in severe chronic stroke

    PubMed Central

    Ramos-Murguialday, Ander; García-Cossio, Eliana; Walter, Armin; Cho, Woosang; Broetz, Doris; Bogdan, Martin; Cohen, Leonardo G; Birbaumer, Niels

    2015-01-01

    Objective Stroke is a leading cause of long-term motor disability. Stroke patients with severe hand weakness do not profit from rehabilitative treatments. Recently, brain-controlled robotics and sequential functional electrical stimulation allowed some improvement. However, for such therapies to succeed, it is required to decode patients' intentions for different arm movements. Here, we evaluated whether residual muscle activity could be used to predict movements from paralyzed joints in severely impaired chronic stroke patients. Methods Muscle activity was recorded with surface-electromyography (EMG) in 41 patients, with severe hand weakness (Fugl-Meyer Assessment [FMA] hand subscores of 2.93 ± 2.7), in order to decode their intention to perform six different motions of the affected arm, required for voluntary muscle activity and to control neuroprostheses. Decoding of paretic and nonparetic muscle activity was performed using a feed-forward neural network classifier. The contribution of each muscle to the intended movement was determined. Results Decoding of up to six arm movements was accurate (>65%) in more than 97% of nonparetic and 46% of paretic muscles. Interpretation These results demonstrate that some level of neuronal innervation to the paretic muscle remains preserved and can be used to implement neurorehabilitative treatments in 46% of patients with severe paralysis and extensive cortical and/or subcortical lesions. Such decoding may allow these patients for the first time after stroke to control different motions of arm prostheses through muscle-triggered rehabilitative treatments. PMID:25642429

  18. GTP-Binding Proteins Inhibit cAMP Activation of Chloride Channels in Cystic Fibrosis Airway Epithelial Cells

    NASA Astrophysics Data System (ADS)

    Schwiebert, Erik M.; Kizer, Neil; Gruenert, Dieter C.; Stanton, Bruce A.

    1992-11-01

    Cystic fibrosis (CF) is a genetic disease characterized, in part, by defective regulation of Cl^- secretion by airway epithelial cells. In CF, cAMP does not activate Cl^- channels in the apical membrane of airway epithelial cells. We report here whole-cell patch-clamp studies demonstrating that pertussis toxin, which uncouples heterotrimeric GTP-binding proteins (G proteins) from their receptors, and guanosine 5'-[β-thio]diphosphate, which prevents G proteins from interacting with their effectors, increase Cl^- currents and restore cAMP-activated Cl^- currents in airway epithelial cells isolated from CF patients. In contrast, the G protein activators guanosine 5'-[γ-thio]triphosphate and AlF^-_4 reduce Cl^- currents and inhibit cAMP from activating Cl^- currents in normal airway epithelial cells. In CF cells treated with pertussis toxin or guanosine 5'-[β-thio]diphosphate and in normal cells, cAMP activates a Cl^- conductance that has properties similar to CF transmembrane-conductance regulator Cl^- channels. We conclude that heterotrimeric G proteins inhibit cAMP-activated Cl^- currents in airway epithelial cells and that modulation of the inhibitory G protein signaling pathway may have the therapeutic potential for improving cAMP-activated Cl^- secretion in CF.

  19. IMD-4690, a novel specific inhibitor for plasminogen activator inhibitor-1, reduces allergic airway remodeling in a mouse model of chronic asthma via regulating angiogenesis and remodeling-related mediators.

    PubMed

    Tezuka, Toshifumi; Ogawa, Hirohisa; Azuma, Masahiko; Goto, Hisatsugu; Uehara, Hisanori; Aono, Yoshinori; Hanibuchi, Masaki; Yamaguchi, Yoichi; Fujikawa, Tomoyuki; Itai, Akiko; Nishioka, Yasuhiko

    2015-01-01

    Plasminogen activator inhibitor (PAI)-1 is the principal inhibitor of plasminogen activators, and is responsible for the degradation of fibrin and extracellular matrix. IMD-4690 is a newly synthesized inhibitor for PAI-1, whereas the effect on allergic airway inflammation and remodeling is still unclear. We examined the in vivo effects by using a chronic allergen exposure model of bronchial asthma in mice. The model was generated by an immune challenge for 8 weeks with house dust mite antigen, Dermatophagoides pteronyssinus (Dp). IMD-4690 was intraperitoneally administered during the challenge. Lung histopathology, hyperresponsiveness and the concentrations of mediators in lung homogenates were analyzed. The amount of active PAI-1 in the lungs was increased in mice treated with Dp. Administration with IMD-4690 reduced an active/total PAI-1 ratio. IMD-4690 also reduced the number of bronchial eosinophils in accordance with the decreased expressions of Th2 cytokines in the lung homogenates. Airway remodeling was inhibited by reducing subepithelial collagen deposition, smooth muscle hypertrophy, and angiogenesis. The effects of IMD-4690 were partly mediated by the regulation of TGF-β, HGF and matrix metalloproteinase. These results suggest that PAI-1 plays crucial roles in airway inflammation and remodeling, and IMD-4690, a specific PAI-1 inhibitor, may have therapeutic potential for patients with refractory asthma due to airway remodeling. PMID:25785861

  20. Mechanical Properties of the Upper Airway

    PubMed Central

    Strohl, Kingman P.; Butler, James P.; Malhotra, Atul

    2013-01-01

    The importance of the upper airway (nose, pharynx, and larynx) in health and in the pathogenesis of sleep apnea, asthma, and other airway diseases, discussed elsewhere in the Comprehensive Physiology series, prompts this review of the biomechanical properties and functional aspects of the upper airway. There is a literature based on anatomic or structural descriptions in static circumstances, albeit studied in limited numbers of individuals in both health and disease. As for dynamic features, the literature is limited to studies of pressure and flow through all or parts of the upper airway and to the effects of muscle activation on such features; however, the links between structure and function through airway size, shape, and compliance remain a topic that is completely open for investigation, particularly through analyses using concepts of fluid and structural mechanics. Throughout are included both historically seminal references, as well as those serving as signposts or updated reviews. This article should be considered a resource for concepts needed for the application of biomechanical models of upper airway physiology, applicable to understanding the pathophysiology of disease and anticipated results of treatment interventions. PMID:23723026

  1. Sensory neuropeptides and airway function.

    PubMed

    Solway, J; Leff, A R

    1991-12-01

    Sensory nerves synthesize tachykinins and calcitonin-gene related peptide and package these neuropeptides together in synaptic vesicles. Stimulation of these C-fibers by a range of chemical and physical factors results in afferent neuronal conduction that elicits central parasympathetic reflexes and in antidromic conduction that results in local release of neuropeptides through the axon reflex. In the airways, sensory neuropeptides act on bronchial smooth muscle, the mucosal vasculature, and submucosal glands to promote airflow obstruction, hyperemia, microvascular hyperpermeability, and mucus hypersecretion. In addition, tachykinins potentiate cholinergic neurotransmission. Proinflammatory effects of these peptides also promote the recruitment, adherence, and activation of granulocytes that may further exacerbate neurogenic inflammation (i.e., neuropeptide-induced plasma extravasation and vasodilation). Enzymatic degradation limits the physiological effects of tachykinins but may be impaired by respiratory infection or other factors. Given their sensitivity to noxious compounds and physical stimuli and their potent effects on airway function, it is possible that neuropeptide-containing sensory nerves play an important role in mediating airway responses in human disease. Supporting this view are the striking phenomenological similarities between hyperpnea-induced bronchoconstriction (HIB) in guinea pigs and HIB in patients with exercise-induced asthma. Endogenous tachykinins released from airway sensory nerves mediate HIB in guinea pigs and also cause hyperpnea-induced bronchovascular hyperpermeability in these animals. On the basis of these observations, it is reasonable to speculate that sensory neuropeptides participate in the pathogenesis of hyperpnea-induced airflow obstruction in human asthmatic subjects as well. PMID:1663932

  2. Impact of varying physical activity levels on airway sensitivity and bronchodilation in healthy humans.

    PubMed

    Smith, Joshua R; Kurti, Stephanie P; Johnson, Ariel M; Kolmer, Sarah A; Harms, Craig

    2015-12-01

    The purpose of this study was to determine if the amount of physical activity influences airway sensitivity and bronchodilation in healthy subjects across a range of physical activity levels. Thirty healthy subjects (age, 21.9 ± 2.6 years; 13 men/17 women) with normal pulmonary function reported to the laboratory on 2 separate occasions where they were randomized to breathe either hypertonic saline (HS) (nebulized hypertonic saline (25%) for 20 min) or HS followed by 5 deep inspirations (DIs), which has been reported to bronchodilate the airways. Pulmonary function tests (PFTs) were performed prior to both conditions and following the HS breathing or 5 DIs. Moderate to vigorous physical activity (MVPA) level was measured via accelerometer worn for 7 days. Following the HS breathing, forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) significantly decreased from baseline by -11.8% ± 8.4% and -9.3% ± 6.7%, respectively. A 2-segment linear model determined significant relationships between MVPA and percent change in FEV1 (r = 0.50) and FVC (r = 0.55). MVPA above ∼497 and ∼500 min/week for FEV1 and FVC, respectively, resulted in minor additional improvements (p > 0.05) in PFTs following the HS breathing. Following the DIs, FEV1 and FVC decreased (p < 0.05) by -7.3% ± 8.6% and -5.7% ± 5.7%, respectively, from baseline, but were not related (p > 0.05) to MVPA. In conclusion, these data demonstrate that higher MVPA levels attenuated airway sensitivity but not bronchodilation in healthy subjects. PMID:26575101

  3. Acid phosphatase and protease activities in immobilized rat skeletal muscles

    NASA Technical Reports Server (NTRS)

    Witzmann, F. A.; Troup, J. P.; Fitts, R. H.

    1982-01-01

    The effect of hind-limb immobilization on selected Iysosomal enzyme activities was studied in rat hing-limb muscles composed primarily of type 1. 2A, or 2B fibers. Following immobilization, acid protease and acid phosphatase both exhibited signifcant increases in their activity per unit weight in all three fiber types. Acid phosphatase activity increased at day 14 of immobilization in the three muscles and returned to control levels by day 21. Acid protease activity also changed biphasically, displaying a higher and earlier rise than acid phosphatase. The pattern of change in acid protease, but not acid phosphatase, closely parallels observed muscle wasting. The present data therefore demonstrate enhanced proteolytic capacity of all three fiber types early during muscular atrophy. In addition, the data suggest a dependence of basal hydrolytic and proteolytic activities and their adaptive response to immobilization on muscle fiber composition.

  4. Respiratory Muscle Activity During Simultaneous Stationary Cycling and Inspiratory Muscle Training.

    PubMed

    Hellyer, Nathan J; Folsom, Ian A; Gaz, Dan V; Kakuk, Alynn C; Mack, Jessica L; Ver Mulm, Jacyln A

    2015-12-01

    Inspiratory muscle training (IMT) strengthens the muscles of respiration, improves breathing efficiency, and increases fitness. The IMT is generally performed independently of aerobic exercise; however, it is not clear whether there is added benefit of performing the IMT while simultaneously performing aerobic exercise in terms of activating and strengthening inspiratory muscles. The purpose of our study was to determine the effect of IMT on respiratory muscle electromyography (EMG) activity during stationary cycling in the upright and drops postures as compared with that when the IMT was performed alone. Diaphragm and sternocleidomastoid EMG activity was measured under different resting and cycling postures, with and without the use of the IMT at 40% maximal inspiratory pressure (n = 10; mean age 37). Cycling in an upright posture while simultaneously performing the IMT resulted in a significantly greater diaphragm EMG activity than while performing the IMT at rest in upright or drops postures (p ≤ 0.05). Cycling in drops postures while performing the IMT had a significantly greater diaphragm EMG activity than when performing the IMT at rest in either upright or drops postures (p ≤ 0.05). Sternocleidomastoid muscle activity increased with both cycling and IMT, although posture had little effect. These results support our hypothesis in that the IMT while cycling increases respiratory EMG activity to a significantly greater extent than when performing the IMT solely at rest, suggesting that the combination of IMT and cycling may provide an additive training effect. PMID:26584054

  5. Breakpoints in ventilation, cerebral and muscle oxygenation, and muscle activity during an incremental cycling exercise

    PubMed Central

    Racinais, Sebastien; Buchheit, Martin; Girard, Olivier

    2014-01-01

    The aim of this study was to locate the breakpoints of cerebral and muscle oxygenation and muscle electrical activity during a ramp exercise in reference to the first and second ventilatory thresholds. Twenty-five cyclists completed a maximal ramp test on an electromagnetically braked cycle-ergometer with a rate of increment of 25 W/min. Expired gazes (breath-by-breath), prefrontal cortex and vastus lateralis (VL) oxygenation [Near-infrared spectroscopy (NIRS)] together with electromyographic (EMG) Root Mean Square (RMS) activity for the VL, rectus femoris (RF), and biceps femoris (BF) muscles were continuously assessed. There was a non-linear increase in both cerebral deoxyhemoglobin (at 56 ± 13% of the exercise) and oxyhemoglobin (56 ± 8% of exercise) concomitantly to the first ventilatory threshold (57 ± 6% of exercise, p > 0.86, Cohen's d < 0.1). Cerebral deoxyhemoglobin further increased (87 ± 10% of exercise) while oxyhemoglobin reached a plateau/decreased (86 ± 8% of exercise) after the second ventilatory threshold (81 ± 6% of exercise, p < 0.05, d > 0.8). We identified one threshold only for muscle parameters with a non-linear decrease in muscle oxyhemoglobin (78 ± 9% of exercise), attenuation in muscle deoxyhemoglobin (80 ± 8% of exercise), and increase in EMG activity of VL (89 ± 5% of exercise), RF (82 ± 14% of exercise), and BF (85 ± 9% of exercise). The thresholds in BF and VL EMG activity occurred after the second ventilatory threshold (p < 0.05, d > 0.6). Our results suggest that the metabolic and ventilatory events characterizing this latter cardiopulmonary threshold may affect both cerebral and muscle oxygenation levels, and in turn, muscle recruitment responses. PMID:24782786

  6. Ozonolysis products of membrane fatty acids activate eicosanoid metabolism in human airway epithelial cells

    SciTech Connect

    Leikauf, G.D.; Zhao, Q.; Zhou, S.; Santrock, J. )

    1993-12-01

    When inhaled, ozone reacts at the airway luminal surface with unsaturated fatty acids contained in the extracellular fluid and plasma membrane to form an aldehyde and hydroxyhydroperoxide. The resulting hydroxyhydroperoxide degrades in aqueous systems to yield a second aldehyde and hydrogen peroxide (H2O2). Previously, we demonstrated that ozone can augment eicosanoid metabolism in bovine airway epithelial cells. To examine structure-activity relationships of ozone-fatty acid degradation products on eicosanoid metabolism in human airway epithelial cells, 3-, 6-, and 9-carbon saturated aldehydes and hydroxyhydroperoxides were synthesized and purified. Eicosanoid metabolism was evaluated by determination of total 3H-activity release from confluent cells previously incubated with [3H]arachidonic acid and by identification of specific metabolites with high performance liquid chromatography and radioimmunoassay. The major metabolites detected were prostaglandin E2, prostaglandin F2 alpha, and 15-hydroxyeicosatetraenoic acid. The 9-carbon aldehyde, nonanal, in contrast to 3- or 6-carbon aldehydes, stimulated release at concentrations > or = 100 microM, suggesting that the stimulatory effect increases with increasing chain length. When tested under identical conditions, the 3-, 6-, and 9-carbon hydroxyhydroperoxides were more potent than the corresponding aldehydes. Again, a greater effect was noted when the chain length was increased. One possible explanation for the increased potency of the hydroxyhydroperoxides over the aldehydes could be due to degradation of the hydroxyhydroperoxide into H2O2 and aldehyde. We consider this an unlikely explanation because responses varied with chain length (although each hydroxyhydroperoxide would produce an equivalent amount of H2O2) and because exposure to H2O2 alone or H2O2 plus hexanal produced a response dissimilar to 1-hydroxy-1-hexanehydroperoxide.

  7. Retracted: Hyaluronan Activation of the Nlrp3 Inflammasome Contributes to the Development of Airway Hyperresponsiveness

    PubMed Central

    Feng, Feifei; Li, Zhuowei; Potts-Kant, Erin N.; Wu, Yiming; Foster, W. Michael; Williams, Kristi L.

    2012-01-01

    Background: The role of the Nlrp3 inflammasome in nonallergic airway hyperresponsiveness (AHR) has not previously been reported. Recent evidence supports both interleukin (IL) 1β and short fragments of hyaluronan (HA) as contributors to the biological response to inhaled ozone. Objective: Because extracellular secretion of IL-1β requires activation of the inflammasome, we investigated the role of the inflammasome proteins ASC, caspase1, and Nlrp3 in the biological response to ozone and HA. Methods: C57BL/6J wild-type mice and mice deficient in ASC, caspase1, or Nlrp3 were exposed to ozone (1 ppm for 3 hr) or HA followed by analysis of airway resistance, cellular inflammation, and total protein and cytokines in bronchoalveolar lavage fluid (BALF). Transcription levels of IL-1β and IL-18 were determined in two populations of lung macrophages. In addition, we examined levels of cleaved caspase1 and cleaved IL-1β as markers of inflammasome activation in isolated alveolar macrophages harvested from BALF from HA-treated mice. Results: We observed that genes of the Nlrp3 inflammasome were required for development of AHR following exposure to either ozone or HA fragments. These genes are partially required for the cellular inflammatory response to ozone. The expression of IL-1β mRNA in alveolar macrophages was up-regulated after either ozone or HA challenge and was not dependent on the Nlrp3 inflammasome. However, soluble levels of IL-1β protein were dependent on the inflammasome after challenge with either ozone or HA. HA challenge resulted in cleavage of macrophage-derived caspase1 and IL-1β, suggesting a role for alveolar macrophages in Nlrp3-dependent AHR. Conclusions: The Nlrp3 inflammasome is required for the development of ozone-induced reactive airways disease. PMID:23010656

  8. Pseudomonas aeruginosa biofilm-associated homoserine lactone C12 rapidly activates apoptosis in airway epithelia

    PubMed Central

    Schwarzer, Christian; Fu, Zhu; Patanwala, Maria; Hum, Lauren; Lopez-Guzman, Mirielle; Illek, Beate; Kong, Weidong; Lynch, Susan V.; Machen, Terry E.

    2014-01-01

    Pseudomonas aeruginosa (PA) forms biofilms in lungs of cystic fibrosis CF) patients, a process regulated by quorum sensing molecules including N-(3-oxododecanoyl)-L-homoserine lactone, C12. C12 (10–100 μM) rapidly triggered events commonly associated with the intrinsic apoptotic pathway in JME (CFΔF508CFTR, nasal surface) epithelial cells: depolarization of mitochondrial (mito) membrane potential (Δψmito) and release of cytochrome C (cytoC) from mitos into cytosol and activation of caspases 3/7, 8 and 9. C12 also had novel effects on the endoplasmic reticulum (release of both Ca2+ and ER-targeted GFP and oxidized contents into the cytosol). Effects began within 5 minutes and were complete in 1–2 hrs. C12 caused similar activation of caspases and release of cytoC from mitos in Calu-3 (wtCFTR, bronchial gland) cells, showing that C12-triggered responses occurred similarly in different airway epithelial types. C12 had nearly identical effects on three key aspects of the apoptosis response (caspase 3/7, depolarization of Δψmito and reduction of redox potential in the ER) in JME and CFTR-corrected JME cells (adenoviral expression), showing that CFTR was likely not an important regulator of C12-triggered apoptosis in airway epithelia. Exposure of airway cultures to biofilms from PAO1wt caused depolarization of Δψmito and increases in Cacyto like 10–50 μM C12. In contrast, biofilms from PAO1ΔlasI (C12 deficient) had no effect, suggesting that C12 from P. aeruginosa biofilms may contribute to accumulation of apoptotic cells that cannot be cleared from CF lungs. A model to explain the effects of C12 is proposed. PMID:22233488

  9. Effect of craniocervical posture on abdominal muscle activities

    PubMed Central

    Su, Jung Gil; Won, Shin Ji; Gak, Hwangbo

    2016-01-01

    [Purpose] The aim of this study was to investigate the influence of the craniocervical posture on abdominal muscle activities in hook-lying position. [Subjects] This study recruited 12 healthy young adults. [Methods] Each subject was asked to adopt a supine position with the hip and knee flexed at 60°. Surface electromyographic signals of transversus abdominis/internal oblique, rectus abdominis, and external oblique in different craniocervical postures (extension, neutral, and flexion) were compared. [Results] The transversus abdominis and rectus abdominis showed increased muscle activities in craniocervical flexion compared to craniocervical extension and neutral position. Greater muscle activities of the external oblique were seen in craniocervical flexion than in craniocervical extension. [Conclusion] Craniocervical flexion was found to be effective to increase the abdominal muscle activities. Consideration of craniocervical posture is recommended when performing trunk stabilization exercises. PMID:27065558

  10. Demonstrating Electrical Activity in Nerve and Muscle. Part I

    ERIC Educational Resources Information Center

    Robinson, D. J.

    1975-01-01

    Describes a demonstration for showing the electrical activity in nerve and muscle including action potentials, refractory period of a nerve, and fatigue. Presents instructions for constructing an amplifier, electronic stimulator, and force transducer. (GS)

  11. Neural control of glutamine synthetase activity in rat skeletal muscles.

    PubMed

    Feng, B; Konagaya, M; Konagaya, Y; Thomas, J W; Banner, C; Mill, J; Max, S R

    1990-05-01

    The mechanism of glutamine synthetase induction in rat skeletal muscle after denervation or limb immobilization was investigated. Adult male rats were subjected to midthigh section of the sciatic nerve. At 1, 2, and 5 h and 1, 2, and 7 days after denervation, rats were killed and denervated, and contralateral control soleus and plantaris muscles were excised, weighted, homogenized, and assayed for glutamine synthetase. Glutamine synthetase activity increased approximately twofold 1 h after denervation in both muscles. By 7 days postdenervation enzyme activity had increased to three times the control level in plantaris muscle and to four times the control level in soleus muscle. Increased enzyme activity after nerve section was associated with increased maximum velocity with no change in apparent Michaelis constant. Immunotitration with an antiglutamine synthetase antibody suggested that denervation caused an increase in the number of glutamine synthetase molecules in muscle. However, Northern-blot analysis revealed no increase in the steady-state level of glutamine synthetase mRNA after denervation. A mixing experiment failed to yield evidence for the presence of a soluble factor involved in regulating the activity of glutamine synthetase in denervated muscle. A combination of denervation and dexamethasone injections resulted in additive increases in glutamine synthetase. Thus the mechanism underlying increased glutamine synthetase after denervation appears to be posttranscriptional and is distinct from that of the glucocorticoid-mediated glutamine synthetase induction previously described by us. PMID:1970709

  12. Enhanced muscle activity during lumbar extension exercise with pelvic stabilization

    PubMed Central

    Lee, Ho-Seong

    2015-01-01

    The purpose of this study was to investigate whether pelvic stabilization affects multifidus (MF) and iliocostalis lumborum (IL) muscle activities during dynamic extension exercise. Nine males (age, 25.1±6.3 yr; height, 176.6±2.4 cm; body mass, 74.9±6.7 kg) performed an isometric lumbar extension strength test and dynamic exercise in an upright seated position with or without pelvic stabilization. The electromyography and muscle strength of the MF and IL muscles were measured when the subjects performed the isometric lumbar extension strength test at the trunk angle 110°, 146°, and 182°. In addition, the trunk extensor muscle activities were measured using 50% muscle strength of maximum isometric strength during a dynamic trunk extension exercise. The MF and IL muscle activities were significantly higher at 110°, 146°, and 182° with pelvic stabilization than that without pelvic stabilization during the isometric lumbar extension strength test (P<0.05) and the dynamic exercise (P<0.05). These results suggest that the lumbar extension exercise with pelvic stabilization may be more effective for MF and IL muscle activity compared to that without pelvic stabilization. PMID:26730390

  13. Coupling of airway ciliary activity and mucin secretion to mechanical stresses by purinergic signaling.

    PubMed

    Davis, C William; Lazarowski, Eduardo

    2008-11-30

    The mucociliary clearance system is comprised of three components, ion transport activities controlling the height of airway surface liquid (ASL), mucin secretion, and ciliary activity. These activities in humans are controlled principally by local agonists, extracellular nucleotides and nucleosides released from the epithelium. Importantly, mechanical stresses stimulate goblet cell mucin secretion, ciliary beating, and Cl- and fluid secretion through mechanically induced nucleotide release. Emerging evidence also implicates co-secretion of nucleotides and mucin from goblet cells as a source of extracellular agonist. At rest, ATP is released onto airway surfaces at approximately 370fmol/mincm2, but only approximately 3% of released ATP is recovered in ASL. Secreted UTP meets with a similar fate. A wide variety of hydrolytic and transphosphorylating ecto-enzymes convert the triphosphate nucleotides into ADP, AMP, and adenosine, UDP, UMP, and uridine. Of these, ATP, adenosine, UTP, and UDP act as agonists at apical P2Y2 (ATP, UTP), P2Y6 (UDP), and A2B (adenosine) receptors on ciliated and/or goblet cells to regulate mucociliary clearance. PMID:18635403

  14. Pituitary Adenylate Cyclase-Activating Polypeptide Reverses Ammonium Metavanadate-Induced Airway Hyperresponsiveness in Rats

    PubMed Central

    Tlili, Mounira; Rouatbi, Sonia; Sriha, Badreddine; Ben Rhouma, Khémais; Sakly, Mohsen; Vaudry, David; Wurtz, Olivier; Tebourbi, Olfa

    2015-01-01

    The rate of atmospheric vanadium is constantly increasing due to fossil fuel combustion. This environmental pollution favours vanadium exposure in particular to its vanadate form, causing occupational bronchial asthma and bronchitis. Based on the well admitted bronchodilator properties of the pituitary adenylate cyclase-activating polypeptide (PACAP), we investigated the ability of this neuropeptide to reverse the vanadate-induced airway hyperresponsiveness in rats. Exposure to ammonium metavanadate aerosols (5 mg/m3/h) for 15 minutes induced 4 hours later an array of pathophysiological events, including increase of bronchial resistance and histological alterations, activation of proinflammatory alveolar macrophages, and increased oxidative stress status. Powerfully, PACAP inhalation (0.1 mM) for 10 minutes alleviated many of these deleterious effects as demonstrated by a decrease of bronchial resistance and histological restoration. PACAP reduced the level of expression of mRNA encoding inflammatory chemokines (MIP-1α, MIP-2, and KC) and cytokines (IL-1α and TNF-α) in alveolar macrophages and improved the antioxidant status. PACAP reverses the vanadate-induced airway hyperresponsiveness not only through its bronchodilator activity but also by counteracting the proinflammatory and prooxidative effects of the metal. Then, the development of stable analogs of PACAP could represent a promising therapeutic alternative for the treatment of inflammatory respiratory disorders. PMID:26199679

  15. Baroreflex modulation of muscle sympathetic nerve activity during posthandgrip muscle ischemia in humans

    NASA Technical Reports Server (NTRS)

    Cui, J.; Wilson, T. E.; Shibasaki, M.; Hodges, N. A.; Crandall, C. G.

    2001-01-01

    To identify whether muscle metaboreceptor stimulation alters baroreflex control of muscle sympathetic nerve activity (MSNA), MSNA, beat-by-beat arterial blood pressure (Finapres), and electrocardiogram were recorded in 11 healthy subjects in the supine position. Subjects performed 2 min of isometric handgrip exercise at 40% of maximal voluntary contraction followed by 2.5 min of posthandgrip muscle ischemia. During muscle ischemia, blood pressure was lowered and then raised by intravenous bolus infusions of sodium nitroprusside and phenylephrine HCl, respectively. The slope of the relationship between MSNA and diastolic blood pressure was more negative (P < 0.001) during posthandgrip muscle ischemia (-201.9 +/- 20.4 units. beat(-1). mmHg(-1)) when compared with control conditions (-142.7 +/- 17.3 units. beat(-1). mmHg(-1)). No significant change in the slope of the relationship between heart rate and systolic blood pressure was observed. However, both curves shifted during postexercise ischemia to accommodate the elevation in blood pressure and MSNA that occurs with this condition. These data suggest that the sensitivity of baroreflex modulation of MSNA is elevated by muscle metaboreceptor stimulation, whereas the sensitivity of baroreflex of modulate heart rate is unchanged during posthandgrip muscle ischemia.

  16. Activity Dependent Signal Transduction in Skeletal Muscle

    NASA Technical Reports Server (NTRS)

    Hamilton, Susan L.

    1999-01-01

    The overall goals of this project are: 1) to define the initial signal transduction events whereby the removal of gravitational load from antigravity muscles, such as the soleus, triggers muscle atrophy, and 2) to develop countermeasures to prevent this from happening. Our rationale for this approach is that, if countermeasures can be developed to regulate these early events, we could avoid having to deal with the multiple cascades of events that occur downstream from the initial event. One of our major findings is that hind limb suspension causes an early and sustained increase in intracellular Ca(2+) concentration ([Ca (2+)](sub i)). In most cells the consequences of changes in ([Ca (2+)](sub i))depend on the amplitude, frequency and duration of the Ca(2+) signal and on other factors in the intracellular environment. We propose that muscle remodeling in microgravity represents a change in the balance among several CA(2+) regulated signal transduction pathways, in particular those involving the transcription factors NFAT and NFkB and the pro-apoptotic protein BAD. Other Ca(2+) sensitive pathways involving PKC, ras, rac, and CaM kinase II may also contribute to muscle remodeling.

  17. Redox regulation of muscle adaptations to contractile activity and aging

    PubMed Central

    2015-01-01

    Superoxide and nitric oxide are generated by skeletal muscle, and these species are increased by contractile activity. Mitochondria have long been assumed to play the primary role in generation of superoxide in muscle, but recent studies indicate that, during contractile activity, membrane-localized NADPH oxidase(s) rapidly generate(s) superoxide that plays a role in redox signaling. This process is important in upregulation of rapid and specific cytoprotective responses that aid maintenance of cell viability following contractile activity, but the overall extent to which redox signaling contributes to regulation of muscle metabolism and homeostasis following contractile activity is currently unclear, as is identification of key redox-sensitive protein targets involved in these processes. Reactive oxygen and nitrogen species have also been implicated in the loss of muscle mass and function that occurs with aging, although recent work has questioned whether oxidative damage plays a key role in these processes. A failure of redox signaling occurs in muscle during aging and may contribute to the age-related loss of muscle fibers. Whether such changes in redox signaling reflect primary age-related changes or are secondary to the fundamental mechanisms is unclear. For instance, denervated muscle fibers within muscles from aged rodents or humans appear to generate large amounts of mitochondrial hydrogen peroxide that could influence adjacent innervated fibers. Thus, in this instance, a “secondary” source of reactive oxygen species may be potentially generated as a result of a primary age-related pathology (loss of neurons), but, nevertheless, may contribute to loss of muscle mass and function during aging. PMID:25792715

  18. Cationic Amphiphiles Increase Activity of Aminoglycoside Antibiotic Tobramycin in the Presence of Airway Polyelectrolytes

    SciTech Connect

    Purdy Drew, Kirstin R.; Sanders, Lori K.; Culumber, Zachary W.; Zribi, Olena; Wong, Gerard C.L.

    2009-06-17

    It is empirically known that anionic polyelectrolytes present in cystic fibrosis (CF) airways due to bacterial infection significantly decrease the activity of cationic antimicrobials via electrostatic binding. In this work, we use synchrotron small-angle X-ray scattering to investigate the interaction between tobramycin, an aminoglycoside antibiotic commonly administered to CF patients via inhalation, with DNA, which is found in high concentrations in the CF airway. We find that interactions between DNA and tobramycin are significantly modified by the presence of mixtures of amphiphilic molecules. We measure a hierarchy of self-assembled structures formed between tobramycin, DNA, and the amphiphile mixtures and show how interactions between these components can be controlled. Results indicate that mixtures of cationic and negative curvature amphiphiles optimized for DNA binding via charge matching and curvature matching can competitively displace bound tobramycin from DNA and thereby drastically suppress tobramycin-DNA binding and resultant antimicrobial inactivation. Growth inhibition assays confirm the increased activity of tobramycin in the presence of DNA with the addition of the amphiphiles. These results suggest that optimized cationic amphiphile solutions have the potential to enhance antimicrobial function in highly infected environments that contain increased concentrations of anionic inflammatory polymers.

  19. Cationic Amphiphiles Increase Activity of Aminoglycoside Antibiotic Tobramycin in the Presence of Airway Polyelectrolytes

    SciTech Connect

    Drew, K.R.Purdy; Sanders, L.K.; Culumber, Z.W.; Zribi, O.; Wong, G.C.L.

    2009-05-21

    It is empirically known that anionic polyelectrolytes present in cystic fibrosis (CF) airways due to bacterial infection significantly decrease the activity of cationic antimicrobials via electrostatic binding. In this work, we use synchrotron small-angle X-ray scattering to investigate the interaction between tobramycin, an aminoglycoside antibiotic commonly administered to CF patients via inhalation, with DNA, which is found in high concentrations in the CF airway. We find that interactions between DNA and tobramycin are significantly modified by the presence of mixtures of amphiphilic molecules. We measure a hierarchy of self-assembled structures formed between tobramycin, DNA, and the amphiphile mixtures and show how interactions between these components can be controlled. Results indicate that mixtures of cationic and negative curvature amphiphiles optimized for DNA binding via charge matching and curvature matching can competitively displace bound tobramycin from DNA and thereby drastically suppress tobramycin-DNA binding and resultant antimicrobial inactivation. Growth inhibition assays confirm the increased activity of tobramycin in the presence of DNA with the addition of the amphiphiles. These results suggest that optimized cationic amphiphile solutions have the potential to enhance antimicrobial function in highly infected environments that contain increased concentrations of anionic inflammatory polymers.

  20. Nicotine enhances murine airway contractile responses to kinin receptor agonists via activation of JNK- and PDE4-related intracellular pathways

    PubMed Central

    2010-01-01

    Background Nicotine plays an important role in cigarette-smoke-associated airway disease. The present study was designed to examine if nicotine could induce airway hyperresponsiveness through kinin receptors, and if so, explore the underlying mechanisms involved. Methods Murine tracheal segments were cultured for 1, 2 or 4 days in serum-free DMEM medium in presence of nicotine (1 and 10 μM) or vehicle (DMSO). Contractile responses induced by kinin B1 receptor agonist, des-Arg9-bradykinin, and B2 receptor agonist, bradykinin, were monitored with myographs. The B1 and B2 receptor mRNA expressions were semi-quantified using real-time PCR and their corresponding protein expressions assessed with confocal-microscopy-based immunohistochemistry. Various pharmacological inhibitors were used for studying intracellular signaling pathways. Results Four days of organ culture with nicotine concentration-dependently increased kinin B1 and B2 receptor-mediated airway contractions, without altering the kinin receptor-mediated relaxations. No such increase was seen at day 1 or day 2. The airway contractile responses to 5-HT, acetylcholine and endothelin receptor agonists remained unaffected by nicotine. Two different neuronal nicotinic receptor antagonists MG624 and hexamethonium blocked the nicotine-induced effects. The enhanced contractile responses were accompanied by increased mRNA and protein expression for both kinin receptors, suggesting the involvement of transcriptional mechanisms. Confocal-microscopy-based immunohistochemistry showed that 4 days of nicotine treatment induced activation (phosphorylation) of c-Jun N-terminal kinase (JNK), but not extracellular signal-regulated kinase 1 and 2 (ERK1/2) and p38. Inhibition of JNK with its specific inhibitor SP600125 abolished the nicotine-induced effects on kinin receptor-mediated contractions and reverted the enhanced receptor mRNA expression. Administration of phosphodiesterase inhibitors (YM976 and theophylline

  1. Activated Muscle Satellite Cells Chase Ghosts.

    PubMed

    Mourikis, Philippos; Relaix, Frédéric

    2016-02-01

    The in vivo behaviors of skeletal muscle stem cells, i.e., satellite cells, during homeostasis and after injury are poorly understood. In this issue of Cell Stem Cell, Webster et al. (2016) now perform a tour de force intravital microscopic analysis of this population, showing that "ghost fiber" remnants act as scaffolds to guide satellite cell divisions after injury. PMID:26849298

  2. Effects of Physical Activity and Inactivity on Muscle Fatigue

    PubMed Central

    Bogdanis, Gregory C.

    2012-01-01

    The aim of this review was to examine the mechanisms by which physical activity and inactivity modify muscle fatigue. It is well known that acute or chronic increases in physical activity result in structural, metabolic, hormonal, neural, and molecular adaptations that increase the level of force or power that can be sustained by a muscle. These adaptations depend on the type, intensity, and volume of the exercise stimulus, but recent studies have highlighted the role of high intensity, short-duration exercise as a time-efficient method to achieve both anaerobic and aerobic/endurance type adaptations. The factors that determine the fatigue profile of a muscle during intense exercise include muscle fiber composition, neuromuscular characteristics, high energy metabolite stores, buffering capacity, ionic regulation, capillarization, and mitochondrial density. Muscle fiber-type transformation during exercise training is usually toward the intermediate type IIA at the expense of both type I and IIx myosin heavy-chain isoforms. High-intensity training results in increases of both glycolytic and oxidative enzymes, muscle capillarization, improved phosphocreatine resynthesis and regulation of K+, H+, and lactate ions. Decreases of the habitual activity level due to injury or sedentary lifestyle result in partial or even compete reversal of the adaptations due to previous training, manifested by reductions in fiber cross-sectional area, decreased oxidative capacity, and capillarization. Complete immobilization due to injury results in markedly decreased force output and fatigue resistance. Muscle unloading reduces electromyographic activity and causes muscle atrophy and significant decreases in capillarization and oxidative enzymes activity. The last part of the review discusses the beneficial effects of intermittent high-intensity exercise training in patients with different health conditions to demonstrate the powerful effect of exercise on health and well being. PMID

  3. Activity of latissimus dorsi muscle during inspiratory threshold loads.

    PubMed

    Orozco-Levi, M; Gea, J; Monells, J; Aran, X; Aguar, M C; Broquetas, J M

    1995-03-01

    The ability of the latissimus dorsi muscle (LD) to participate as an accessory inspiratory muscle has been the subject of controversy. Electromyographic (EGM) activity of LD was evaluated in 11 healthy subjects (aged 30 +/- 2 yrs; forced expiratory volume in one second (FEV1) 106 +/- 5% predicted; maximal inspiratory pressure (Pmax), 120 +/- 6 cmH2O) under different breathing conditions. The ipsilateral biceps brachii was chosen as the control muscle. The EMG was recorded from surface electrodes, but needle electrodes were also used for LD evaluation in a subset of three subjects. The EMG signal from both muscles was recorded simultaneously, rectified and integrated, with subtraction of the electrocardiographic signal. Situations evaluated were: 1) maximal voluntary contraction (MVC); 2) apnoea; and 3) breathing under progressive inspiratory threshold loads (20-100% Pmax, at 20% intervals). A close relationship was evident between LD recordings from surface and needle electrodes (r = 0.975). Activity of LD at baseline was 1.8 +/- 0.4% MVC, and showed a phasic increase during inspiration under loads. This change had a linear tendency and was significant for loads corresponding to 40, 60, 80 and 100% of Pmax when compared to the control muscle. At this latter level, LD activity was equivalent to 32 +/- 5% MVC (range 11-61%), whereas mean activity of the control muscle was less than 7.5% MVC.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7789491

  4. Airway Hydration, Apical K(+) Secretion, and the Large-Conductance, Ca(2+)-activated and Voltage-dependent Potassium (BK) Channel.

    PubMed

    Kis, Adrian; Krick, Stefanie; Baumlin, Nathalie; Salathe, Matthias

    2016-04-01

    Large-conductance, calcium-activated, and voltage-gated K(+) (BK) channels are expressed in many tissues of the human body, where they play important roles in signaling not only in excitable but also in nonexcitable cells. Because BK channel properties are rendered in part by their association with four β and four γ subunits, their channel function can differ drastically, depending on in which cellular system they are expressed. Recent studies verify the importance of apically expressed BK channels for airway surface liquid homeostasis and therefore of their significant role in mucociliary clearance. Here, we review evidence that inflammatory cytokines, which contribute to airway diseases, can lead to reduced BK activity via a functional down-regulation of the γ regulatory subunit LRRC26. Therefore, manipulation of LRRC26 and pharmacological opening of BK channels represent two novel concepts of targeting epithelial dysfunction in inflammatory airway diseases. PMID:27115952

  5. Sexual Dimorphism in the Regulation of Estrogen, Progesterone, and Androgen Receptors by Sex Steroids in the Rat Airway Smooth Muscle Cells

    PubMed Central

    Zarazúa, Abraham; González-Arenas, Aliesha; Ramírez-Vélez, Gabriela; Bazán-Perkins, Blanca; Guerra-Araiza, Christian; Campos-Lara, María G.

    2016-01-01

    The role of sex hormones in lung is known. The three main sex steroid receptors, estrogen, progesterone, and androgen, have not been sufficiently studied in airway smooth muscle cells (ASMC), and the sex hormone regulation on these receptors is unknown. We examined the presence and regulation of sex hormone receptors in female and male rat ASMC by Western blotting and flow cytometry. Gonadectomized rats were treated with 17β-estradiol, progesterone, 17β-estradiol + progesterone, or testosterone. ASMC were enzymatically isolated from tracheas and bronchi. The experiments were performed with double staining flow cytometry (anti-α-actin smooth muscle and antibodies to each hormone receptor). ERα, ERβ, tPR, and AR were detected in females or males. ERα was upregulated by E2 and T and downregulated by P4 in females; in males, ERα was downregulated by P4, E + P, and T. ERβ was downregulated by each treatment in females, and only by E + P and T in males. tPR was downregulated by P4, E + P, and T in females. No hormonal regulation was observed in male receptors. AR was downregulated in males treated with E + P and T. We have shown the occurrence of sex hormone receptors in ASMC and their regulation by the sex hormones in female and male rats. PMID:27110242

  6. Sexual Dimorphism in the Regulation of Estrogen, Progesterone, and Androgen Receptors by Sex Steroids in the Rat Airway Smooth Muscle Cells.

    PubMed

    Zarazúa, Abraham; González-Arenas, Aliesha; Ramírez-Vélez, Gabriela; Bazán-Perkins, Blanca; Guerra-Araiza, Christian; Campos-Lara, María G

    2016-01-01

    The role of sex hormones in lung is known. The three main sex steroid receptors, estrogen, progesterone, and androgen, have not been sufficiently studied in airway smooth muscle cells (ASMC), and the sex hormone regulation on these receptors is unknown. We examined the presence and regulation of sex hormone receptors in female and male rat ASMC by Western blotting and flow cytometry. Gonadectomized rats were treated with 17β-estradiol, progesterone, 17β-estradiol + progesterone, or testosterone. ASMC were enzymatically isolated from tracheas and bronchi. The experiments were performed with double staining flow cytometry (anti-α-actin smooth muscle and antibodies to each hormone receptor). ERα, ERβ, tPR, and AR were detected in females or males. ERα was upregulated by E2 and T and downregulated by P4 in females; in males, ERα was downregulated by P4, E + P, and T. ERβ was downregulated by each treatment in females, and only by E + P and T in males. tPR was downregulated by P4, E + P, and T in females. No hormonal regulation was observed in male receptors. AR was downregulated in males treated with E + P and T. We have shown the occurrence of sex hormone receptors in ASMC and their regulation by the sex hormones in female and male rats. PMID:27110242

  7. Muscle activity detection in electromyograms recorded during periodic movements.

    PubMed

    Spulák, Daniel; Cmejla, Roman; Bačáková, Radka; Kračmar, Bronislav; Satrapová, Lenka; Novotný, Petr

    2014-04-01

    Muscle coordination during periodic movements is often studied using the average envelope of the electromyographic (EMG) signal. We show that this method causes a loss of important information, and potentially gives rise to errors in analysis of muscle activity coordination. We created four simulated two-channel surface EMG signals, in order to compare the results of muscle onset/cessation detection, performed on the average EMG envelope and the EMG envelopes in every single movement cycle. Our results show that the common method using the average EMG envelope is unable to reveal certain important characteristics of the EMG signals, while the analysis performed on individual cycles accentuates this information. This ability was verified on 16-channel surface EMGs obtained during walking and cycling. By detecting muscle activity in individual movement cycles, we could observe fine changes in muscle coordination. Moreover, muscles with questionable reliability of activity detection were distinguished and highlighted in the presented summary figures. In the second part of the paper, our publicly available set of MATLAB files for surface EMG signal processing is described. PMID:24561347

  8. The syndrome of continuous muscle fibre activity following gold therapy.

    PubMed

    Grisold, W; Mamoli, B

    1984-01-01

    A 72-year-old man suffering from arthritis received a total dose of 500 mg sodium aurothiomalate during a period of 5 months. His clinical state then deteriorated and he had to be hospitalized. Upon admission he was bedridden, his level of consciousness was slightly impaired, he was confused and respiration was laboured. Continuous muscle activity was noted on all extremities and at first, erroneously, fasciculations were diagnosed. The EMG exhibited continuous muscle fibre activity consisting of duplets, triplets and multiplets. The discharges occurred in an irregular pattern; when various muscles were examined at the same time no synchronicity could be observed between muscle discharges. In the left m. deltoideus an increased percentage of polyphasic potentials was found, whereas mean duration of motor unit potentials was normal. Spontaneous activity remained unchanged during sleep and administration of intravenous diazepam or phenytoin. Blocking of ulnar nerve at either elbow or wrist level did not stop spontaneous activity in m. abductor digiti quinti. Ischaemia increased the amount of discharges after 7 min. Within 4 months after termination of gold therapy the patient's condition improved and he was discharged from hospital. Regular EMG follow-up after 8 months showed complete cessation of abnormal spontaneous activities. Nerve conduction velocities were normal except for markedly reduced compound action potential in peroneal nerves. Continuous muscle fibre activity as a side-effect of gold therapy is described. PMID:6440953

  9. Muscle Activity Adaptations to Spinal Tissue Creep in the Presence of Muscle Fatigue

    PubMed Central

    Nougarou, François

    2016-01-01

    Aim The aim of this study was to identify adaptations in muscle activity distribution to spinal tissue creep in presence of muscle fatigue. Methods Twenty-three healthy participants performed a fatigue task before and after 30 minutes of passive spinal tissue deformation in flexion. Right and left erector spinae activity was recorded using large-arrays surface electromyography (EMG). To characterize muscle activity distribution, dispersion was used. During the fatigue task, EMG amplitude root mean square (RMS), median frequency and dispersion in x- and y-axis were compared before and after spinal creep. Results Important fatigue-related changes in EMG median frequency were observed during muscle fatigue. Median frequency values showed a significant main creep effect, with lower median frequency values on the left side under the creep condition (p≤0.0001). A significant main creep effect on RMS values was also observed as RMS values were higher after creep deformation on the right side (p = 0.014); a similar tendency, although not significant, was observed on the left side (p = 0.06). A significant creep effects for x-axis dispersion values was observed, with higher dispersion values following the deformation protocol on the left side (p≤0.001). Regarding y-axis dispersion values, a significant creep x fatigue interaction effect was observed on the left side (p = 0.016); a similar tendency, although not significant, was observed on the right side (p = 0.08). Conclusion Combined muscle fatigue and creep deformation of spinal tissues led to changes in muscle activity amplitude, frequency domain and distribution. PMID:26866911

  10. Curine inhibits eosinophil activation and airway hyper-responsiveness in a mouse model of allergic asthma

    SciTech Connect

    Ribeiro-Filho, Jaime; Calheiros, Andrea Surrage; Vieira-de-Abreu, Adriana; Moraes de Carvalho, Katharinne Ingrid; Silva Mendes, Diego da; Melo, Christianne Bandeira; Martins, Marco Aurélio; Silva Dias, Celidarque da; Piuvezam, Márcia Regina; and others

    2013-11-15

    Allergic asthma is a chronic inflammatory airway disease with increasing prevalence around the world. Current asthma therapy includes drugs that usually cause significant side effects, justifying the search for new anti-asthmatic drugs. Curine is a bisbenzylisoquinoline alkaloid that modulates calcium influx in many cell types; however, its anti-allergic and putative toxic effects remain to be elucidated. Our aim was to investigate the effects of curine on eosinophil activation and airway hyper-responsiveness (AHR) and to characterize its potential toxic effects. We used a mouse model of allergic asthma induced by sensitization and challenge with ovalbumin (OVA) to evaluate the anti-allergic effects of oral treatment with curine. The oral administration of curine significantly inhibited eosinophilic inflammation, eosinophil lipid body formation and AHR in animals challenged with OVA compared with animals in the untreated group. The curine treatment also reduced eotaxin and IL-13 production triggered by OVA. Verapamil, a calcium channel antagonist, had similar anti-allergic properties, and curine pre-treatment inhibited the calcium-induced tracheal contractile response ex-vivo, suggesting that the mechanism by which curine exerts its effects is through the inhibition of a calcium-dependent response. A toxicological evaluation showed that orally administered curine did not significantly alter the biochemical, hematological, behavioral and physical parameters measured in the experimental animals compared with saline-treated animals. In conclusion, curine showed anti-allergic activity through mechanisms that involve inhibition of IL-13 and eotaxin and of Ca{sup ++} influx, without inducing evident toxicity and as such, has the potential for the development of anti-asthmatic drugs. - Highlights: • Curine is a bisbenzylisoquinoline alkaloid from Chondrodendron platyphyllum. • Curine inhibits eosinophil influx and activation and airway hyper-responsiveness. • Curine

  11. Adult Non-Cystic Fibrosis Bronchiectasis Is Characterised by Airway Luminal Th17 Pathway Activation

    PubMed Central

    Chen, Alice C.-H.; Martin, Megan L.; Lourie, Rohan; Rogers, Geraint B.; Burr, Lucy D.; Hasnain, Sumaira Z.; Bowler, Simon D.; McGuckin, Michael A.; Serisier, David J.

    2015-01-01

    Background Non-cystic fibrosis (CF) bronchiectasis is characterised by chronic airway infection and neutrophilic inflammation, which we hypothesised would be associated with Th17 pathway activation. Methods Th17 pathway cytokines were quantified in bronchoalveolar lavage fluid (BALF), and gene expression of IL-17A, IL-1β, IL-8 and IL-23 determined from endobronchial biopsies (EBx) in 41 stable bronchiectasis subjects and 20 healthy controls. Relationships between IL-17A levels and infection status, important clinical measures and subsequent Pseudomonas aeruginosa infection were determined. Results BALF levels of all Th17 cytokines (median (IQR) pg/mL) were significantly higher in bronchiectasis than control subjects, including IL-17A (1.73 (1.19, 3.23) vs. 0.27 (0.24, 0.35), 95% CI 1.05 to 2.21, p<0.0001) and IL-23 (9.48 (4.79, 15.75) vs. 0.70 (0.43, 1.79), 95% CI 4.68 to 11.21, p<0.0001). However, BALF IL-17A levels were not associated with clinical measures or airway microbiology, nor predictive of subsequent P. aeruginosa infection. Furthermore, gene expression of IL-17A in bronchiectasis EBx did not differ from control. In contrast, gene expression (relative to medians of controls) in bronchiectasis EBx was significantly higher than control for IL1β (4.12 (1.24, 8.05) vs 1 (0.13, 2.95), 95% CI 0.05 to 4.07, p = 0.04) and IL-8 (3.75 (1.64, 11.27) vs 1 (0.54, 3.89), 95% CI 0.32 to 4.87, p = 0.02) and BALF IL-8 and IL-1α levels showed significant relationships with clinical measures and airway microbiology. P. aeruginosa infection was associated with increased levels of IL-8 while Haemophilus influenzae was associated with increased IL-1α. Conclusions and Clinical Relevance Established adult non-CF bronchiectasis is characterised by luminal Th17 pathway activation, however this pathway may be relatively less important than activation of non-antigen-specific innate neutrophilic immunity. PMID:25822228

  12. Feasible muscle activation ranges based on inverse dynamics analyses of human walking.

    PubMed

    Simpson, Cole S; Sohn, M Hongchul; Allen, Jessica L; Ting, Lena H

    2015-09-18

    Although it is possible to produce the same movement using an infinite number of different muscle activation patterns owing to musculoskeletal redundancy, the degree to which observed variations in muscle activity can deviate from optimal solutions computed from biomechanical models is not known. Here, we examined the range of biomechanically permitted activation levels in individual muscles during human walking using a detailed musculoskeletal model and experimentally-measured kinetics and kinematics. Feasible muscle activation ranges define the minimum and maximum possible level of each muscle's activation that satisfy inverse dynamics joint torques assuming that all other muscles can vary their activation as needed. During walking, 73% of the muscles had feasible muscle activation ranges that were greater than 95% of the total muscle activation range over more than 95% of the gait cycle, indicating that, individually, most muscles could be fully active or fully inactive while still satisfying inverse dynamics joint torques. Moreover, the shapes of the feasible muscle activation ranges did not resemble previously-reported muscle activation patterns nor optimal solutions, i.e. static optimization and computed muscle control, that are based on the same biomechanical constraints. Our results demonstrate that joint torque requirements from standard inverse dynamics calculations are insufficient to define the activation of individual muscles during walking in healthy individuals. Identifying feasible muscle activation ranges may be an effective way to evaluate the impact of additional biomechanical and/or neural constraints on possible versus actual muscle activity in both normal and impaired movements. PMID:26300401

  13. The effect of platelet activating factor antagonist on ozone-induced airway inflammation and bronchial hyperresponsiveness in guinea pigs

    SciTech Connect

    Tan, W.C.; Bethel, R.A. )

    1992-10-01

    We investigated the role of platelet-activating factor (PAF) in ozone-induced airway responses by examining the effects of L659,989, a potent PAF antagonist, on bronchial hyperresponsiveness and airway inflammation. Twenty-four male guinea pigs were studied in four equal groups. Total lung resistance (RL) in intubated and spontaneously breathing animals was measured in a constant-volume body plethysmograph. Dose-response curves to methacholine were determined in all animals at the start of the experiment. These were repeated on a separate day after the following types of treatments: air exposure in Group 1, intraperitoneally administered alcohol and air exposure in Group 2; intraperitoneally administered alcohol and ozone exposure in Group 3, and intraperitoneally administered L659,989 (a specific PAF antagonist), 5 mg/kg dissolved in alcohol, and ozone exposure in Group 4. Bronchoalveolar lavage (BAL) was performed after the second methacholine challenge, and the bronchial mucosa was also examined for inflammatory cells. Exposure to 3 ppm ozone for 2 h resulted in a three-doubling concentration increase in bronchial responsiveness, which was not significantly inhibited by prior treatment with L659,989. Ozone induced a 1.8-fold increase in BAL total cell count, increased eosinophilic influx into the airways, and increased eosinophilic infiltration in the bronchial mucosa, which were all not inhibited by L659,989 pretreatment. The results suggest that PAF may not have an essential role in ozone-induced airway hyperresponsiveness and nonallergic airway inflammation.

  14. T cells are necessary for ILC2 activation in house dust mite-induced allergic airway inflammation in mice.

    PubMed

    Li, Bobby W S; de Bruijn, Marjolein J W; Tindemans, Irma; Lukkes, Melanie; KleinJan, Alex; Hoogsteden, Henk C; Hendriks, Rudi W

    2016-06-01

    Allergic asthma is a chronic inflammation of the airways mediated by an adaptive type 2 immune response. Upon allergen exposure, group 2 innate lymphoid cells (ILC2s) can be rapidly activated and represent an early innate source of IL-5 and IL-13. Here, we used a house dust mite (HDM)-driven asthma mouse model to study the induction of ILC2s in allergic airway inflammation. In BALF, lungs, and lymph nodes, ILC2 activation is critically dependent on prior sensitization with HDM. Importantly, T cells are required for ILC2 induction, whereby T-cell activation precedes ILC2 induction. During HDM-driven allergic airway inflammation the accumulation of ILC2s in BALF is IL-33 independent, although infiltrating ILC2s produce less cytokines in Il33(-/-) mice. Transfer of in vitro polarized OVA-specific OT-II Th2 cells alone or in combination with Th17 cells followed by OVA and HDM challenge is not sufficient to induce ILC2, despite significant eosinophilic inflammation and T-cell activation. In this asthma model, ILC2s are therefore not an early source of Th2 cytokines, but rather contribute to type 2 inflammation in which Th2 cells play a key role. Taken together, ILC2 induction in HDM-mediated allergic airway inflammation in mice critically depends on activation of T cells. PMID:27062360

  15. Respiratory-related activity of cricothyroid muscle in awake normal humans.

    PubMed

    Wheatley, J R; Brancatisano, A; Engel, L A

    1991-05-01

    The role of the cricothyroid muscle (CT) in respiration is unclear. To examine the respiratory-related electrical activity of the CT, we measured its electromyogram (EMG) and compared it with that of the alae nasi (AN) in eight healthy subjects. During quiet breathing the CT EMG phasing was inspiratory in seven subjects. This pattern was similar to the AN with respect to phasing and shape of the integrated EMG. The onset of phasic CT and AN activity related to inspiration preceded flow by 173 +/- 39 and 570 +/- 76 (SE) ms, respectively (P less than 0.01). We measured the duration from onset of phasic activity to peak of the EMG (TA) and the total cycle duration (TT). TA/TT of the CT was 0.29 +/- 0.02, similar to that of the AN (0.28 +/- 0.03). Inspiratory resistive loading, panting, and voluntary hyperventilation increased CT activity above the peak level seen during tidal breathing. Voluntary glottic closure increased CT activity to a level above tonic but below peak tidal activity. The findings suggest that the phasic electrical activity of the CT simulates predominantly that of an upper airway dilator. PMID:1864803

  16. Influence of playing wind instruments on activity of masticatory muscles.

    PubMed

    Gotouda, A; Yamaguchi, T; Okada, K; Matsuki, T; Gotouda, S; Inoue, N

    2007-09-01

    The aim of this study was to elucidate the influence of change in sound tone of playing wind instruments on activity of jaw-closing muscles and the effect of sustained playing for a long time on fatigue of jaw-closing muscles. Electromyograms (EMG) of 19 brass instrument players and 14 woodwind instrument players were measured while playing instruments in tuning tone and high tone and under other conditions. Nine brass instrument players and nine woodwind instrument players played instruments for 90 min. Before and after the exercise, power spectral analyses of EMG from masseter muscles at 50% of maximum voluntary clenching level were performed and mean power frequency (MPF) were calculated. Root mean square (RMS) of EMG in masseter and temporal muscles while playing were slightly larger than those at rest but extremely small in comparison with those during maximum clenching. Root mean square in orbicularis oris and digastric muscles were relatively large when playing instruments. In the brass instrument group, RMS in high tone was significantly higher than that in tuning tone in all muscles examined. In the woodwind instrument group, RMS in high tone was not significantly higher than that in tuning tone in those muscles. Mean power frequency was not decreased after sustained playing in both instrument groups. These findings indicate that contractive load to jaw-closing muscles when playing a wind instrument in both medium and high tone is very small and playing an instrument for a long time does not obviously induce fatigue of jaw-closing muscles. PMID:17716263

  17. Upregulation of TRPM7 augments cell proliferation and interleukin-8 release in airway smooth muscle cells of rats exposed to cigarette smoke.

    PubMed

    Lin, Xiaoling; Yang, Cheng; Huang, Linjie; Chen, Ming; Shi, Jianting; Ouyang, Lihua; Tang, Tiantian; Zhang, Wei; Li, Yiqun; Liang, Ruiyun; Jiang, Shanping

    2016-06-01

    Proliferation and synthetic function (i.e. the capacity to release numerous chemokines and cytokines) of airway smooth muscle cells (ASMCs) are important in airway remodeling induced by cigarette smoke exposure. However, the molecular mechanism has not been clarified. Transient receptor potential cation channel subfamily M member 7 (TRPM7) is expressed ubiquitously and is crucial for the cellular physiological function of many cell types. The present study aimed to detect the expression of TRPM7 in ASMCs from smoke‑exposed rats and determine the importance of TRPM7 in proliferation and interleukin‑8 (IL‑8) release. ASMCs were isolated and cultured from smoke‑exposed rats. Expression levels of TRPM7 were determined by reverse transcription‑polymerase chain reaction, western blot analysis and immunofluorescence. TRPM7 was silenced with TRPM7‑short hairpin RNA lentivirus vector. DNA synthesis, cell number and IL‑8 release of ASMCs induced by cigarette smoke extract (CSE) and tumor necrosis factor‑α (TNF‑α) were assessed using [3H]-thymidine incorporation assay, hemocytometer and enzyme‑linked immunosorbent assay, respectively. It was determined that mRNA and protein expression levels of TRPM7 were increased in ASMCs from smoke‑exposed rats. Stimulation with CSE or TNF‑α elevated DNA synthesis, cell number and IL‑8 release were more marked in ASMCs from smoke‑exposed rats. Silencing of TRPM7 reduced DNA synthesis, cell number and IL‑8 release induced by CSE or TNF‑α in ASMCs from smoke-exposed rats. In conclusion, expression of TRPM7 increased significantly in ASMCs from smoke‑exposed rats and the upregulation of TRPM7 led to augmented cell proliferation and IL-8 release in ASMCs from rats exposed to cigarette smoke. PMID:27108806

  18. Upregulation of TRPM7 augments cell proliferation and interleukin-8 release in airway smooth muscle cells of rats exposed to cigarette smoke

    PubMed Central

    LIN, XIAOLING; YANG, CHENG; HUANG, LINJIE; CHEN, MING; SHI, JIANTING; OUYANG, LIHUA; TANG, TIANTIAN; ZHANG, WEI; LI, YIQUN; LIANG, RUIYUN; JIANG, SHANPING

    2016-01-01

    Proliferation and synthetic function (i.e. the capacity to release numerous chemokines and cytokines) of airway smooth muscle cells (ASMCs) are important in airway remodeling induced by cigarette smoke exposure. However, the molecular mechanism has not been clarified. Transient receptor potential cation channel subfamily M member 7 (TRPM7) is expressed ubiquitously and is crucial for the cellular physiological function of many cell types. The present study aimed to detect the expression of TRPM7 in ASMCs from smoke-exposed rats and determine the importance of TRPM7 in proliferation and interleukin-8 (IL-8) release. ASMCs were isolated and cultured from smoke-exposed rats. Expression levels of TRPM7 were determined by reverse transcription-polymerase chain reaction, western blot analysis and immunofluorescence. TRPM7 was silenced with TRPM7-short hairpin RNA lentivirus vector. DNA synthesis, cell number and IL-8 release of ASMCs induced by cigarette smoke extract (CSE) and tumor necrosis factor-α (TNF-α) were assessed using [3H]-thymidine incorporation assay, hemocytometer and enzyme-linked immunosorbent assay, respectively. It was determined that mRNA and protein expression levels of TRPM7 were increased in ASMCs from smoke-exposed rats. Stimulation with CSE or TNF-α elevated DNA synthesis, cell number and IL-8 release were more marked in ASMCs from smoke-exposed rats. Silencing of TRPM7 reduced DNA synthesis, cell number and IL-8 release induced by CSE or TNF-α in ASMCs from smoke-exposed rats. In conclusion, expression of TRPM7 increased significantly in ASMCs from smoke-exposed rats and the upregulation of TRPM7 led to augmented cell proliferation and IL-8 release in ASMCs from rats exposed to cigarette smoke. PMID:27108806

  19. Contributions of Central Command and Muscle Feedback to Sympathetic Nerve Activity in Contracting Human Skeletal Muscle

    PubMed Central

    Boulton, Daniel; Taylor, Chloe E.; Macefield, Vaughan G.; Green, Simon

    2016-01-01

    During voluntary contractions, muscle sympathetic nerve activity (MSNA) to contracting muscles increases in proportion to force but the underlying mechanisms are not clear. To shed light on these mechanisms, particularly the influences of central command and muscle afferent feedback, the present study tested the hypothesis that MSNA is greater during voluntary compared with electrically-evoked contractions. Seven male subjects performed a series of 1-min isometric dorsiflexion contractions (left leg) separated by 2-min rest periods, alternating between voluntary and electrically-evoked contractions at similar forces (5–10% of maximum). MSNA was recorded continuously (microneurography) from the left peroneal nerve and quantified from cardiac-synchronized, negative-going spikes in the neurogram. Compared with pre-contraction values, MSNA increased by 51 ± 34% (P < 0.01) during voluntary contractions but did not change significantly during electrically-evoked contractions (−8 ± 12%, P > 0.05). MSNA analyzed at 15-s intervals revealed that this effect of voluntary contraction appeared 15–30 s after contraction onset (P < 0.01), remained elevated until the end of contraction, and disappeared within 15 s after contraction. These findings suggest that central command, and not feedback from contracting muscle, is the primary mechanism responsible for the increase in MSNA to contracting muscle. The time-course of MSNA suggests that there is a longer delay in the onset of this effect compared with its cessation after contraction. PMID:27242537

  20. Contributions of Central Command and Muscle Feedback to Sympathetic Nerve Activity in Contracting Human Skeletal Muscle.

    PubMed

    Boulton, Daniel; Taylor, Chloe E; Macefield, Vaughan G; Green, Simon

    2016-01-01

    During voluntary contractions, muscle sympathetic nerve activity (MSNA) to contracting muscles increases in proportion to force but the underlying mechanisms are not clear. To shed light on these mechanisms, particularly the influences of central command and muscle afferent feedback, the present study tested the hypothesis that MSNA is greater during voluntary compared with electrically-evoked contractions. Seven male subjects performed a series of 1-min isometric dorsiflexion contractions (left leg) separated by 2-min rest periods, alternating between voluntary and electrically-evoked contractions at similar forces (5-10% of maximum). MSNA was recorded continuously (microneurography) from the left peroneal nerve and quantified from cardiac-synchronized, negative-going spikes in the neurogram. Compared with pre-contraction values, MSNA increased by 51 ± 34% (P < 0.01) during voluntary contractions but did not change significantly during electrically-evoked contractions (-8 ± 12%, P > 0.05). MSNA analyzed at 15-s intervals revealed that this effect of voluntary contraction appeared 15-30 s after contraction onset (P < 0.01), remained elevated until the end of contraction, and disappeared within 15 s after contraction. These findings suggest that central command, and not feedback from contracting muscle, is the primary mechanism responsible for the increase in MSNA to contracting muscle. The time-course of MSNA suggests that there is a longer delay in the onset of this effect compared with its cessation after contraction. PMID:27242537

  1. Pseudomonas aeruginosa Induced Airway Epithelial Injury Drives Fibroblast Activation: A Mechanism in Chronic Lung Allograft Dysfunction.

    PubMed

    Borthwick, L A; Suwara, M I; Carnell, S C; Green, N J; Mahida, R; Dixon, D; Gillespie, C S; Cartwright, T N; Horabin, J; Walker, A; Olin, E; Rangar, M; Gardner, A; Mann, J; Corris, P A; Mann, D A; Fisher, A J

    2016-06-01

    Bacterial infections after lung transplantation cause airway epithelial injury and are associated with an increased risk of developing bronchiolitis obliterans syndrome. The damaged epithelium is a source of alarmins that activate the innate immune system, yet their ability to activate fibroblasts in the development of bronchiolitis obliterans syndrome has not been evaluated. Two epithelial alarmins were measured longitudinally in bronchoalveolar lavages from lung transplant recipients who developed bronchiolitis obliterans syndrome and were compared to stable controls. In addition, conditioned media from human airway epithelial cells infected with Pseudomonas aeruginosa was applied to lung fibroblasts and inflammatory responses were determined. Interleukin-1 alpha (IL-1α) was increased in bronchoalveolar lavage of lung transplant recipients growing P. aeruginosa (11.5 [5.4-21.8] vs. 2.8 [0.9-9.4] pg/mL, p < 0.01) and was significantly elevated within 3 months of developing bronchiolitis obliterans syndrome (8.3 [1.4-25.1] vs. 3.6 [0.6-17.1] pg/mL, p < 0.01), whereas high mobility group protein B1 remained unchanged. IL-1α positively correlated with elevated bronchoalveolar lavage IL-8 levels (r(2)  = 0.6095, p < 0.0001) and neutrophil percentage (r(2)  = 0.25, p = 0.01). Conditioned media from P. aeruginosa infected epithelial cells induced a potent pro-inflammatory phenotype in fibroblasts via an IL-1α/IL-1R-dependent signaling pathway. In conclusion, we propose that IL-1α may be a novel therapeutic target to limit Pseudomonas associated allograft injury after lung transplantation. PMID:26714197

  2. Mechanism of airway hyperresponsiveness to adenosine induced by allergen challenge in actively sensitized Brown Norway rats

    PubMed Central

    Hannon, J P; Tigani, B; Williams, I; Mazzoni, L; Fozard, J R

    2001-01-01

    We have explored the role of allergen sensitization and challenge in defining the response of the airways of the Brown Norway (BN) rat to adenosine. In naïve animals or in rats sensitized to ovalbumin (OA) adenosine induced only weak bronchoconstrictor responses. Challenge of sensitized animals with OA induced a marked airway hyperresponsiveness to adenosine which was not seen with methacholine or bradykinin. The augmented bronchoconstrictor response to adenosine was not affected by acute bivagotomy or atropine nor mimicked by an i.v. injection of capsaicin. It was, however, blocked selectively by disodium cromoglycate methysergide or ketanserin and reduced in animals treated sub-chronically with compound 48/80. The augmented response to adenosine was associated with increases in the plasma concentrations of both histamine and 5-hydroxytryptamine (5-HT), which were attenuated by pretreatment with disodium cromoglycate, and degranulation of mast cells in the lung. Parenchymal strips from lungs removed from sensitized rats challenged with OA gave augmented bronchoconstrictor responses to adenosine relative to strips from sensitized animals challenged with saline. Responses were inhibited by methysergide and disodium cromoglycate. These data demonstrate a marked augmentation of the bronchoconstrictor response to adenosine in actively sensitized BN rats challenged with OA. The augmented response is primarily a consequence of mast cell activation, leading to the release of 5-HT, which in turn induces bronchoconstriction. Our data further suggest the involvement of a discrete lung-based population of mast cells containing and releasing mainly 5-HT and brought into play by prior exposure to allergen. PMID:11264245

  3. Curine inhibits eosinophil activation and airway hyper-responsiveness in a mouse model of allergic asthma.

    PubMed

    Ribeiro-Filho, Jaime; Calheiros, Andrea Surrage; Vieira-de-Abreu, Adriana; de Carvalho, Katharinne Ingrid Moraes; da Silva Mendes, Diego; Melo, Christianne Bandeira; Martins, Marco Aurélio; da Silva Dias, Celidarque; Piuvezam, Márcia Regina; Bozza, Patrícia T

    2013-11-15

    Allergic asthma is a chronic inflammatory airway disease with increasing prevalence around the world. Current asthma therapy includes drugs that usually cause significant side effects, justifying the search for new anti-asthmatic drugs. Curine is a bisbenzylisoquinoline alkaloid that modulates calcium influx in many cell types; however, its anti-allergic and putative toxic effects remain to be elucidated. Our aim was to investigate the effects of curine on eosinophil activation and airway hyper-responsiveness (AHR) and to characterize its potential toxic effects. We used a mouse model of allergic asthma induced by sensitization and challenge with ovalbumin (OVA) to evaluate the anti-allergic effects of oral treatment with curine. The oral administration of curine significantly inhibited eosinophilic inflammation, eosinophil lipid body formation and AHR in animals challenged with OVA compared with animals in the untreated group. The curine treatment also reduced eotaxin and IL-13 production triggered by OVA. Verapamil, a calcium channel antagonist, had similar anti-allergic properties, and curine pre-treatment inhibited the calcium-induced tracheal contractile response ex-vivo, suggesting that the mechanism by which curine exerts its effects is through the inhibition of a calcium-dependent response. A toxicological evaluation showed that orally administered curine did not significantly alter the biochemical, hematological, behavioral and physical parameters measured in the experimental animals compared with saline-treated animals. In conclusion, curine showed anti-allergic activity through mechanisms that involve inhibition of IL-13 and eotaxin and of Ca(++) influx, without inducing evident toxicity and as such, has the potential for the development of anti-asthmatic drugs. PMID:23994558

  4. How different modes of child delivery influence abdominal muscle activities in the active straight leg raise.

    PubMed

    Kwon, Yu-Jeong; Hyung, Eun-Ju; Yang, Kyung-Hye; Lee, Hyun-Ok

    2014-08-01

    [Purpose] The purpose of this study was to examine the activities of the abdominal muscles of women who had experienced vaginal delivery in comparison with those who had experienced Cesarean childbirth. [Subjects and Methods] A total of 14 subjects (7 vaginal delivery, 7 Cesarean section) performed an active straight leg raise to 20 cm above the ground, and we measured the activities of the internal oblique abdominal muscle, the external oblique abdominal muscle, and the rectus abdominal muscle on both sides using electromyography. The effort required to raise the leg was scored on a Likert scale. Then, the subjects conducted maximum isometric contraction for hip joint flexion with the leg raised at 20 cm, and maximum torque and abdominal muscle activities were measured using electromyography. [Results] During the active straight leg raise, abdominal muscle activities were higher in the Cesarean section subjects. The Likert scale did not show a significant difference. The activities of the abdominal muscles and the maximum torque of the hip joint flexion at maximum isometric contraction were higher in the vaginal delivery subjects. [Conclusion] The abdominal muscles of Cesarean section subjects showed greater recruitment for maintaining pelvic stability during the active straight leg raising, but were relatively weaker when powerful force was required. Therefore, we consider that more abdominal muscle training is necessary for maintaining pelvic stability of Cesarean section subjects. PMID:25202194

  5. IL-17A induces signal transducers and activators of transcription-6-independent airway mucous cell metaplasia.

    PubMed

    Newcomb, Dawn C; Boswell, Madison G; Sherrill, Taylor P; Polosukhin, Vasiliy V; Boyd, Kelli L; Goleniewska, Kasia; Brody, Steven L; Kolls, Jay K; Adler, Kenneth B; Peebles, R Stokes

    2013-06-01

    Mucous cell metaplasia is a hallmark of asthma, and may be mediated by signal transducers and activators of transcription (STAT)-6 signaling. IL-17A is increased in the bronchoalveolar lavage fluid of patients with severe asthma, and IL-17A also increases mucus production in airway epithelial cells. Asthma therapeutics are being developed that inhibit STAT6 signaling, but the role of IL-17A in inducing mucus production in the absence of STAT6 remains unknown. We hypothesized that IL-17A induces mucous cell metaplasia independent of STAT6, and we tested this hypothesis in two murine models in which increased IL-17A protein expression is evident. In the first model, ovalbumin (OVA)-specific D011.10 Th17 cells were adoptively transferred into wild-type (WT) or STAT6 knockout (KO) mice, and the mice were challenged with OVA or PBS. WT-OVA and STAT6 KO-OVA mice demonstrated increased airway IL-17A and IL-13 protein expression and mucous cell metaplasia, compared with WT-PBS or STAT6 KO-PBS mice. In the second model, WT, STAT1 KO, STAT1/STAT6 double KO (DKO), or STAT1/STAT6/IL-17 receptor A (RA) triple KO (TKO) mice were challenged with respiratory syncytial virus (RSV) or mock viral preparation, and the mucous cells were assessed. STAT1 KO-RSV mice demonstrated increased airway mucous cell metaplasia compared with WT-RSV mice. STAT1 KO-RSV and STAT1/STAT6 DKO-RSV mice also demonstrated increased mucous cell metaplasia, compared with STAT1/STAT6/IL17RA TKO-RSV mice. We also treated primary murine tracheal epithelial cells (mTECs) from WT and STAT6 KO mice. STAT6 KO mTECs showed increased periodic acid-Schiff staining with IL-17A but not with IL-13. Thus, asthma therapies targeting STAT6 may increase IL-17A protein expression, without preventing IL-17A-induced mucus production. PMID:23392574

  6. Optimization of Spinal Muscular Atrophy subject's muscle activity during gait

    NASA Astrophysics Data System (ADS)

    Umat, Gazlia; Rambely, Azmin Sham

    2014-06-01

    Spinal Muscular Atrophy (SMA) is a hereditary disease related muscle nerve disorder caused by degeneration of the anterior cells of the spinal cord. SMA is divided into four types according to the degree of seriousness. SMA patients show different gait with normal people. Therefore, this study focused on the effects of SMA patient muscle actions and the difference that exists between SMA subjects and normal subjects. Therefore, the electromyography (EMG) test will be used to track the behavior of muscle during walking and optimization methods are used to get the muscle stress that is capable of doing the work while walking. Involved objective function is non-linear function of the quadratic and cubic functions. The study concludes with a comparison of the objective function using the force that sought to use the moment of previous studies and the objective function using the data obtained from EMG. The results shows that the same muscles, peroneus longus and bisepsfemoris, were used during walking activity by SMA subjects and control subjects. Muscle stress force best solution achieved from part D in simulation carried out.

  7. LIGHT is a crucial mediator of airway remodeling.

    PubMed

    Hung, Jen-Yu; Chiang, Shyh-Ren; Tsai, Ming-Ju; Tsai, Ying-Ming; Chong, Inn-Wen; Shieh, Jiunn-Min; Hsu, Ya-Ling

    2015-05-01

    Chronic inflammatory airway diseases like asthma and chronic obstructive pulmonary disease are major health problems globally. Airway epithelial cells play important role in airway remodeling, which is a critical process in the pathogenesis of diseases. This study aimed to demonstrate that LIGHT, an inflammatory factor secreted by T cells after allergen exposure, is responsible for promoting airway remodeling. LIGHT increased primary human bronchial epithelial cells (HBECs) undergoing epithelial-mesenchymal transition (EMT) and expressing MMP-9. The induction of EMT was associated with increased NF-κB activation and p300/NF-κB association. The interaction of NF-κB with p300 facilitated NF-κB acetylation, which in turn, was bound to the promoter of ZEB1, resulting in E-cadherin downregulation. LIGHT also stimulated HBECs to produce numerous cytokines/chemokines that could worsen airway inflammation. Furthermore, LIGHT enhanced HBECs to secrete activin A, which increased bronchial smooth muscle cell (BSMC) migration. In contrast, depletion of activin A decreased such migration. The findings suggest a new molecular determinant of LIGHT-mediated pathogenic changes in HBECs and that the LIGHT-related vicious cycle involving HBECs and BSMCs may be a potential target for the treatment of chronic inflammation airway diseases with airway remodeling. PMID:25251281

  8. Multivariable Dynamic Ankle Mechanical Impedance With Active Muscles

    PubMed Central

    Lee, Hyunglae; Krebs, Hermano Igo; Hogan, Neville

    2015-01-01

    Multivariable dynamic ankle mechanical impedance in two coupled degrees-of-freedom (DOFs) was quantified when muscles were active. Measurements were performed at five different target activation levels of tibialis anterior and soleus, from 10% to 30% of maximum voluntary contraction (MVC) with increments of 5% MVC. Interestingly, several ankle behaviors characterized in our previous study of the relaxed ankle were observed with muscles active: ankle mechanical impedance in joint coordinates showed responses largely consistent with a second-order system consisting of inertia, viscosity, and stiffness; stiffness was greater in the sagittal plane than in the frontal plane at all activation conditions for all subjects; and the coupling between dorsiflexion–plantarflexion and inversion–eversion was small—the two DOF measurements were well explained by a strictly diagonal impedance matrix. In general, ankle stiffness increased linearly with muscle activation in all directions in the 2-D space formed by the sagittal and frontal planes, but more in the sagittal than in the frontal plane, resulting in an accentuated “peanut shape.” This characterization of young healthy subjects’ ankle mechanical impedance with active muscles will serve as a baseline to investigate pathophysiological ankle behaviors of biomechanically and/or neurologically impaired patients. PMID:25203497

  9. Patterns of arm muscle activation involved in octopus reaching movements.

    PubMed

    Gutfreund, Y; Flash, T; Fiorito, G; Hochner, B

    1998-08-01

    The extreme flexibility of the octopus arm allows it to perform many different movements, yet octopuses reach toward a target in a stereotyped manner using a basic invariant motor structure: a bend traveling from the base of the arm toward the tip (Gutfreund et al., 1996a). To study the neuronal control of these movements, arm muscle activation [electromyogram (EMG)] was measured together with the kinematics of reaching movements. The traveling bend is associated with a propagating wave of muscle activation, with maximal muscle activation slightly preceding the traveling bend. Tonic activation was occasionally maintained afterward. Correlation of the EMG signals with the kinematic variables (velocities and accelerations) reveals that a significant part of the kinematic variability can be explained by the level of muscle activation. Furthermore, the EMG level measured during the initial stages of movement predicts the peak velocity attained toward the end of the reaching movement. These results suggest that feed-forward motor commands play an important role in the control of movement velocity and that simple adjustment of the excitation levels at the initial stages of the movement can set the velocity profile of the whole movement. A simple model of octopus arm extension is proposed in which the driving force is set initially and is then decreased in proportion to arm diameter at the bend. The model qualitatively reproduces the typical velocity profiles of octopus reaching movements, suggesting a simple control mechanism for bend propagation in the octopus arm. PMID:9671683

  10. A viscoplastic model for the active component in cardiac muscle.

    PubMed

    Rubin, M B

    2016-08-01

    The HMK model (Hunter et al. in Prog Biophys Mol Biol 69:289-331, 1998) proposes mechanobiological equations for the influence of intracellular calcium concentration [Formula: see text] on the evolution of bound calcium concentration [Formula: see text] and the tropomyosin kinetics parameter z, which model processes in the active component of the tension in cardiac muscle. The inelastic response due to actin-myosin crossbridge kinetics is modeled in the HMK model with a function Q that depends on the history of the rate of total stretch of the muscle fiber. Here, an alternative model is proposed which models the active component of the muscle fiber as a viscoplastic material. In particular, an evolution equation is proposed for the elastic stretch [Formula: see text] in the active component. Specific forms of the constitutive equations are proposed and used to match experimental data. The proposed viscoplastic formulation allows for separate modeling of three processes: the high rate deactivation of crossbridges causing rapid reduction in active tension; the high but lower rate reactivation of crossbridges causing recovery of active tension; and the low rate relaxation effects characterizing the Hill model of muscles. PMID:26476735

  11. Osteopontin That Is Elevated in the Airways during COPD Impairs the Antibacterial Activity of Common Innate Antibiotics

    PubMed Central

    Mori, Michiko; Keenan, Paul; Mörgelin, Matthias; Erjefält, Jonas S.; Herwald, Heiko; Egesten, Arne; Kasetty, Gopinath

    2016-01-01

    Bacterial infections of the respiratory tract contribute to exacerbations and disease progression in chronic obstructive pulmonary disease (COPD). There is also an increased risk of invasive pneumococcal disease in COPD. The underlying mechanisms are not fully understood but include impaired mucociliary clearance and structural remodeling of the airways. In addition, antimicrobial proteins that are constitutively expressed or induced during inflammatory conditions are an important part of the airway innate host defense. In the present study, we show that osteopontin (OPN), a multifunctional glycoprotein that is highly upregulated in the airways of COPD patients co-localizes with several antimicrobial proteins expressed in the airways. In vitro, OPN bound lactoferrin, secretory leukocyte peptidase inhibitor (SLPI), midkine, human beta defensin-3 (hBD-3), and thymic stromal lymphopoietin (TSLP) but showed low or no affinity for lysozyme and LL-37. Binding of OPN impaired the antibacterial activity against the important bacterial pathogens Streptococcus pneumoniae and Pseudomonas aeruginosa. Interestingly, OPN reduced lysozyme-induced killing of S. pneumoniae, a finding that could be explained by binding of OPN to the bacterial surface, thereby shielding the bacteria. A fragment of OPN generated by elastase of P. aeruginosa retained some inhibitory effect. Some antimicrobial proteins have additional functions. However, the muramidase-activity of lysozyme and the protease inhibitory function of SLPI were not affected by OPN. Taken together, OPN can contribute to the impairment of innate host defense by interfering with the function of antimicrobial proteins, thus increasing the vulnerability to acquire infections during COPD. PMID:26731746

  12. Muscle activation patterns in patients with recurrent shoulder instability

    PubMed Central

    Jaggi, Anju; Noorani, Ali; Malone, Alex; Cowan, Joseph; Lambert, Simon; Bayley, Ian

    2012-01-01

    Purpose: The aim of this study is to present muscle patterns observed with the direction of instability in a series of patients presenting with recurrent shoulder instability. Materials and Methods: A retrospective review was carried out on shoulder instability cases referred for fine wire dynamic electromyography (DEMG) studies at a specialist upper limb centre between 1981 and 2003. An experienced consultant clinical neurophysiologist performed dual needle insertion into four muscles (pectoralis major (PM), latissimus dorsi (LD), anterior deltoid (AD) and infraspinatus (IS)) in shoulders that were suspected to have increased or suppressed activation of muscles that could be contributing to the instability. Raw EMG signals were obtained while subjects performed simple uniplanar movements of the shoulder. The presence or absence of muscle activation was noted and compared to clinical diagnosis and direction of instability. Results: A total of 140 (26.6%) shoulders were referred for fine wire EMG, and 131 studies were completed. Of the shoulders tested, 122 shoulders (93%) were identified as having abnormal patterns and nine had normal patterns. PM was found to be more active in 60% of shoulders presenting with anterior instability. LD was found to be more active in 81% of shoulders with anterior instability and 80% with posterior instability. AD was found to be more active in 22% of shoulders with anterior instability and 18% with posterior instability. IS was found to be inappropriately inactive in only 3% of shoulders with anterior instability but in 25% with posterior instability. Clinical assessment identified 93% of cases suspected to have muscle patterning, but the specificity of the clinical assessment was only correct in 11% of cases. Conclusion: The DEMG results suggest that increased activation of LD may play a role in both anterior and posterior shoulder instability; increased activation of PM may play a role in anterior instability. PMID:23493512

  13. X-ray diffraction of actively shortening muscle.

    PubMed

    Podolsky, R J; St Onge, H; Yu, L; Lymn, R W

    1976-03-01

    Low angle x-ray diffraction patterns were obtained from resting and activated frog sartorius muscles by means of a position-sensitive detector. Although the intensity ratio I10/I11 decreased many-fold upon activation, it was nearly the same during isometric and isotonic contraction. Thus, motion has a much smaller effect on the low order equatorial pattern than the transition from rest to activity. Analysis of the 10 and 11 reflections separately showed that I10 and I11 change reciprocally upon activation, and that they both increase by a small amount in the transition from isometric to isotonic contraction. If the intensity ratio can be taken as a measure of cross-bridge number, the results provide evidence that the drop in force in an actively shortening muscle is due primarily to the influence of motion on the configuration, rather than the number, of cross-bridges. PMID:1062793

  14. Mapping Muscles Activation to Force Perception during Unloading

    PubMed Central

    Toma, Simone; Lacquaniti, Francesco

    2016-01-01

    It has been largely proved that while judging a force humans mainly rely on the motor commands produced to interact with that force (i.e., sense of effort). Despite of a large bulk of previous investigations interested in understanding the contributions of the descending and ascending signals in force perception, very few attempts have been made to link a measure of neural output (i.e., EMG) to the psychophysical performance. Indeed, the amount of correlation between EMG activity and perceptual decisions can be interpreted as an estimate of the contribution of central signals involved in the sensation of force. In this study we investigated this correlation by measuring the muscular activity of eight arm muscles while participants performed a quasi-isometric force detection task. Here we showed a method to quantitatively describe muscular activity (“muscle-metric function”) that was directly comparable to the description of the participants' psychophysical decisions about the stimulus force. We observed that under our experimental conditions, muscle-metric absolute thresholds and the shape of the muscle-metric curves were closely related to those provided by the psychophysics. In fact a global measure of the muscles considered was able to predict approximately 60% of the perceptual decisions total variance. Moreover the inter-subjects differences in psychophysical sensitivity showed high correlation with both participants' muscles sensitivity and participants' joint torques. Overall, our findings gave insights into both the role played by the corticospinal motor commands while performing a force detection task and the influence of the gravitational muscular torque on the estimation of vertical forces. PMID:27032087

  15. Changes in Quadriceps Muscle Activity During Sustained Recreational Alpine Skiing

    PubMed Central

    Kröll, Josef; Müller, Erich; Seifert, John G.; Wakeling, James M.

    2011-01-01

    During a day of skiing thousands of repeated contractions take place. Previous research on prolonged recreational alpine skiing show that physiological changes occur and hence some level of fatigue is inevitable. In the present paper the effect of prolonged skiing on the recruitment and coordination of the muscle activity was investigated. Six subjects performed 24 standardized runs. Muscle activity during the first two (PREskiing) and the last two (POSTskiing) runs was measured from the vastus lateralis (VL) and rectus femoris (RF) using EMG and quantified using wavelet and principal component analysis. The frequency content of the EMG signal shifted in seven out of eight cases significantly towards lower frequencies with highest effects observed for RF on outside leg. A significant pronounced outside leg loading occurred during POSTskiing and the timing of muscle activity peaks occurred more towards turn completion. Specific EMG frequency changes were observed at certain time points throughout the time windows and not over the whole double turn. It is suggested that general muscular fatigue, where additional specific muscle fibers have to be recruited due to the reduced power output of other fibers did not occur. The EMG frequency decrease and intensity changes for RF and VL are caused by altered timing (coordination) within the turn towards a most likely more uncontrolled skiing technique. Hence, these data provide evidence to suggest recreational skiers alter their skiing technique before a potential change in muscle fiber recruitment occurs. Key points The frequency content of the EMG signal shifted in seven out of eight cases significantly towards lower frequencies with highest effects observed for RF. General muscular fatigue, where additional specific fibers have to be recruited due to the reduced power output of other fibers, did not occur. A modified skiing style towards a less functional and hence more uncontrolled skiing technique seems to be a key

  16. Walking at the preferred stride frequency minimizes muscle activity.

    PubMed

    Russell, Daniel M; Apatoczky, Dylan T

    2016-03-01

    This study determined whether walking at the preferred stride frequency minimizes muscle activity compared with other cadences at the same speed. Anthropometric measurements were recorded from 10 subjects and used to estimate their predicted resonant stride frequency. The preferred walking speed and stride frequency were determined from freely adopted walking on a treadmill. For the experimental trials the treadmill was set at each individual's preferred walking speed. Participants walked for 6 min at eight cadences prescribed by an auditory metronome: preferred stride frequency and -35, -25, -15, 0, +15, +25, +35% of predicted resonant stride frequency. Oxygen consumption was measured via gas analysis. Muscle activity of the right leg gastrocnemius (GA), tibialis anterior (TA), biceps femoris (BF) and rectus femoris (RF) muscles was recorded via electromyography (EMG). On average, participants preferred to walk with a stride frequency .07 Hz lower than their predicted resonant stride frequency, however a strong positive correlation was observed between these variables. Stride frequency had a significant and large quadratic effect on VO2 (RLR(2)=.76), and activity of the GA (RLR(2)=.66), TA (RLR(2)=.83), BF (RLR(2)=.70) and RF (RLR(2)=.78) muscles. VO2, GA and TA activity were all minimal at the preferred stride frequency and increased for faster or slower cadences. BF and RF activity were minimal across a broad range of slow frequencies including the preferred stride frequency and increased for faster frequencies. The preferred stride frequency that humans readily adopt during walking minimizes the activation of the GA, TA, BF and RF muscles, which in turn minimizes the overall metabolic cost. PMID:26979903

  17. Fatigue-related firing of muscle nociceptors reduces voluntary activation of ipsilateral but not contralateral lower limb muscles.

    PubMed

    Kennedy, David S; Fitzpatrick, Siobhan C; Gandevia, Simon C; Taylor, Janet L

    2015-02-15

    During fatiguing upper limb exercise, maintained firing of group III/IV muscle afferents can limit voluntary drive to muscles within the same limb. It is not known if this effect occurs in the lower limb. We investigated the effects of group III/IV muscle afferent firing from fatigued ipsilateral and contralateral extensor muscles and ipsilateral flexor muscles of the knee on voluntary activation of the knee extensors. In three experiments, we examined voluntary activation of the knee extensors by measuring changes in superimposed twitches evoked by femoral nerve stimulation. Subjects attended on 2 days for each experiment. On one day a sphygmomanometer cuff occluded blood flow of the fatigued muscles to maintain firing of group III/IV muscle afferents. After a 2-min extensor contraction (experiment 1; n = 9), mean voluntary activation was lower with than without maintained ischemia (47 ± 19% vs. 87 ± 8%, respectively; P < 0.001). After a 2-min knee flexor maximal voluntary contraction (MVC) (experiment 2; n = 8), mean voluntary activation was also lower with than without ischemia (59 ± 21% vs. 79 ± 9%; P < 0.01). After the contralateral (left) MVC (experiment 3; n = 8), mean voluntary activation of the right leg was similar with or without ischemia (92 ± 6% vs. 93 ± 4%; P = 0.65). After fatiguing exercise, activity in group III/IV muscle afferents reduces voluntary activation of the fatigued muscle and nonfatigued antagonist muscles in the same leg. However, group III/IV muscle afferents from the fatigued left leg had no effect on the unfatigued right leg. This suggests that any "crossover" of central fatigue in the lower limbs is not mediated by group III/IV muscle afferents. PMID:25525208

  18. Activity of the Adrenergic Nerve System in the Airways Permeability of Healthy Persons

    PubMed Central

    Gashi, Njazi; Islami, Pëllumb; Mustafa, Lirim; Maloku, Halit; Veseli, Arta; Islami, Hilmi

    2013-01-01

    Objective: In this work, role of the adrenergic nerve system (alpha1 and beta2) in adjustment of the bronchomotor tonus in healthy people was researched. Methods: Parameters of the lung function are determined by Body plethysmography. Raw and ITGV were registered and SRaw was calculated as well. Aerosolization is done with standard aerosolizing machines – Asema. Results: Results gained shows that following the blockade of beta-2 adrenergic receptor with Propranolol (20 mg–aerosol), stimulation of alpha adrenergic receptor with Oxedrine (120 mg-aerosol) and blockage of these receptors with Tolazoline (20 mg-aerosol), does not change significantly the bronchomotor tonus of the tracheobronchial tree (p > 0.1). Meanwhile, stimulation of the beta-2 adrenergic receptor with Hexoprenaline (2 inh × 0.2 mg) is associated with a significant increase of the peripheral resistance of the airways (p < 0.01). Conclusion: This suggests that the activity of the alpha1-adrenergic receptor, unlike the activity of the beta2-adrenergic receptor in the healthy people smooth musculature, is not significant and as such is insufficient to oppose to the tonic activities of the cholinergic system. PMID:24554803

  19. Distending Pressure Did Not Activate Acute Phase or Inflammatory Responses in the Airways and Lungs of Fetal, Preterm Lambs

    PubMed Central

    Petersen, Rebecca Y.; Royse, Emily; Kemp, Matthew W.; Miura, Yuichiro; Noe, Andres; Jobe, Alan H.; Hillman, Noah H.

    2016-01-01

    Background Mechanical ventilation at birth causes airway injury and lung inflammation in preterm sheep. Continuous positive airway pressure (CPAP) is being increasingly used clinically to transition preterm infants at birth. Objective To test if distending pressures will activate acute phase reactants and inflammatory changes in the airways of fetal, preterm lambs. Methods The head and chest of fetal lambs at 128±1 day GA were surgically exteriorized. With placental circulation intact, fetal lambs were then randomized to one of five 15 minute interventions: PEEP of 0, 4, 8, 12, or 16 cmH2O. Recruitment volumes were recorded. Fetal lambs remained on placental support for 30 min after the intervention. The twins of each 0 cmH2O animal served as controls. Fetal lung fluid (FLF), bronchoalveolar lavage fluid (BAL), right mainstem bronchi and peripheral lung tissue were evaluated for inflammation. Results Recruitment volume increased from 0.4±0.04 mL/kg at 4 cmH2O to 2.4±0.3 mL/kg at 16 cmH2O. The lambs were surfactant deficient, and all pressures were below the opening inflection pressure on pressure-volume curve. mRNA expression of early response genes and pro-inflammatory cytokines did not increase in airway tissue or lung tissue at any pressure compared to controls. FLF and BAL also did not have increases in early response proteins. No histologic changes or Egr-1 activation was present at the pressures used. Conclusion Distending pressures as high as 16 cmH2O did not recruit lung volume at birth and did not increase markers of injury in the lung or airways in non-breathing preterm fetal sheep. PMID:27463520

  20. Non-crossbridge stiffness in active muscle fibres.

    PubMed

    Colombini, Barbara; Nocella, Marta; Bagni, Maria Angela

    2016-01-01

    Stretching of an activated skeletal muscle induces a transient tension increase followed by a period during which the tension remains elevated well above the isometric level at an almost constant value. This excess of tension in response to stretching has been called 'static tension' and attributed to an increase in fibre stiffness above the resting value, named 'static stiffness'. This observation was originally made, by our group, in frog intact muscle fibres and has been confirmed more recently, by us, in mammalian intact fibres. Following stimulation, fibre stiffness starts to increase during the latent period well before crossbridge force generation and it is present throughout the whole contraction in both single twitches and tetani. Static stiffness is dependent on sarcomere length in a different way from crossbridge force and is independent of stretching amplitude and velocity. Static stiffness follows a time course which is distinct from that of active force and very similar to the myoplasmic calcium concentration time course. We therefore hypothesize that static stiffness is due to a calcium-dependent stiffening of a non-crossbridge sarcomere structure, such as the titin filament. According to this hypothesis, titin, in addition to its well-recognized role in determining the muscle passive tension, could have a role during muscle activity. PMID:26792325

  1. [Effect of vanadate on Ca++-activation in skeletal muscle].

    PubMed

    Son'kin, B Ia; Bukatina, A E

    1983-01-01

    Vanadate (0.1 mM) reduces tension of glycerinated rabbit psoas muscle fibers, shifts tension--pCa curve to lower pCa, increases the rate constant of delayed tension development and changes dependence of this rate constant on the level of Ca2+-activation. Vanadate influence stops the increase of the rate constant with the rise of Ca++-activated tension. Since actin-myosin-ADP complex is dissociated by vanadate, the muscle performance at low activation levels is supposed to be conditioned largely by the cross-bridges interacting with actin of the actin blocks switched on by myosin-ADP. Kinetics of such cross-bridges differs from that of the cross bridges interacting with actin activated by Ca++ binding to troponin C. PMID:6556917

  2. Surgical Airway

    PubMed Central

    Patel, Sapna A; Meyer, Tanya K

    2014-01-01

    Close to 3% of all intubation attempts are considered difficult airways, for which a plan for a surgical airway should be considered. Our article provides an overview of the different types of surgical airways. This article provides a comprehensive review of the main types of surgical airways, relevant anatomy, necessary equipment, indications and contraindications, preparation and positioning, technique, complications, and tips for management. It is important to remember that the placement of a surgical airway is a lifesaving procedure and should be considered in any setting when one “cannot intubate, cannot ventilate”. PMID:24741501

  3. Particulate matter (PM₁₀) induces metalloprotease activity and invasion in airway epithelial cells.

    PubMed

    Morales-Bárcenas, Rocío; Chirino, Yolanda I; Sánchez-Pérez, Yesennia; Osornio-Vargas, Álvaro Román; Melendez-Zajgla, Jorge; Rosas, Irma; García-Cuellar, Claudia María

    2015-09-17

    Airborne particulate matter with an aerodynamic diameter ≤ 10 μm (PM10) is a risk factor for the development of lung diseases and cancer. The aim of this work was to identify alterations in airway epithelial (A549) cells induced by PM10 that could explain how subtoxic exposure (10 μg/cm(2)) promotes a more aggressive in vitro phenotype. Our results showed that cells exposed to PM10 from an industrial zone (IZ) and an urban commercial zone (CZ) induced an increase in protease activity and invasiveness; however, the cell mechanism is different, as only PM10 from CZ up-regulated the activity of metalloproteases MMP-2 and MMP-9 and disrupted E-cadherin/β-catenin expression after 48 h of exposure. These in vitro findings are relevant in terms of the mechanism action of PM10 in lung epithelial cells, which could be helpful in understanding the pathogenesis of some human illness associated with highly polluted cities. PMID:26047787

  4. Effect of intranasal rosiglitazone on airway inflammation and remodeling in a murine model of chronic asthma

    PubMed Central

    Lee, Hwa Young; Rhee, Chin Kook; Kang, Ji Young; Park, Chan Kwon; Lee, Sook Young; Kwon, Soon Suk; Kim, Young Kyoon; Yoon, Hyoung Kyu

    2016-01-01

    Background/Aims: Asthma is characterized by airway hyperresponsiveness, inflammation, and remodeling. Peroxisome proliferator-activated receptors have been reported to regulate inflammatory responses in many cells. In this study, we examined the effects of intranasal rosiglitazone on airway remodeling in a chronic asthma model. Methods: We developed a mouse model of airway remodeling, including smooth muscle thickening, in which ovalbumin (OVA)-sensitized mice were repeatedly exposed to intranasal OVA administration twice per week for 3 months. Mice were treated intranasally with rosiglitazone with or without an antagonist during OVA challenge. We determined airway inflammation and the degree of airway remodeling by smooth muscle actin area and collagen deposition. Results: Mice chronically exposed to OVA developed sustained eosinophilic airway inflammation, compared with control mice. Additionally, the mice developed features of airway remodeling, including thickening of the peribronchial smooth muscle layer. Administration of rosiglitazone intranasally inhibited the eosinophilic inflammation significantly, and, importantly, airway smooth muscle remodeling in mice chronically exposed to OVA. Expression of Toll-like receptor (TLR)-4 and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) was increased in the OVA group and decreased in the rosiglitazone group. Co-treatment with GW9660 (a rosiglitazone antagonist) and rosiglitazone increased the expression of TLR-4 and NF-κB. Conclusions: These results suggest that intranasal administration of rosiglitazone can prevent not only air way inf lammation but also air way remodeling associated with chronic allergen challenge. This beneficial effect is mediated by inhibition of TLR-4 and NF-κB pathways. PMID:26767862

  5. Decreased phosphofructokinase activity in skeletal muscle of diabetic rats.

    PubMed

    Bauer, B A; Younathan, E S

    1984-01-01

    The activities of phosphofructokinase, aldolase and pyruvate kinase were diminished in extracts from skeletal muscle of streptozotocin diabetic rats, whereas the activities of glucose phosphate isomerase and phosphoglucomutase were not changed. Treatment of diabetic rats with insulin restored the activity of phosphofructokinase to normal. A kinetic study of the partially purified enzyme from normal and diabetic rats showed identical Michaelis constants for ATP and equal sensitivity to inhibition by excess of this substrate. Extracts of quick frozen muscle from diabetic rats had higher levels of citrate (an inhibitor of phosphofructokinase) and lower levels of D-fructose-1,6-bisphosphate and D-glucose-1,6-bisphosphate (activators of this enzyme). The levels of D-fructose-6-phosphate, D-glucose-6-phosphate, ATP, ADP and AMP were the same for the two groups. Our data suggest that the in vivo decrease of phosphofructokinase activity in skeletal muscle of diabetic rats is due to a decrease in the level of the enzymatically active protein as well as to an unfavorable change in the level of several of its allosteric modulators. PMID:6237837

  6. A novel thiol compound, N-acetylcysteine amide, attenuates allergic airway disease by regulating activation of NF-kappaB and hypoxia-inducible factor-1alpha.

    PubMed

    Lee, Kyung Sun; Kim, So Ri; Park, Hee Sun; Park, Seoung Ju; Min, Kyung Hoon; Lee, Ka Young; Choe, Yeong Hun; Hong, Sang Hyun; Han, Hyo Jin; Lee, Young Rae; Kim, Jong Suk; Atlas, Daphne; Lee, Yong Chul

    2007-12-31

    Reactive oxygen species (ROS) play an important role in the pathogenesis of airway inflammation and hyperresponsiveness. Recent studies have demonstrated that antioxidants are able to reduce airway inflammation and hyperreactivity in animal models of allergic airway disease. A newly developed antioxidant, small molecular weight thiol compound, N-acetylcysteine amide (AD4) has been shown to increase cellular levels of glutathione and to attenuate oxidative stress related disorders such as Alzheimer's disease, Parkinson's disease, and multiple sclerosis. However, the effects of AD4 on allergic airway disease such as asthma are unknown. We used ovalbumin (OVA)-inhaled mice to evaluate the role of AD4 in allergic airway disease. In this study with OVA-inhaled mice, the increased ROS generation, the increased levels of Th2 cytokines and VEGF, the increased vascular permeability, the increased mucus production, and the increased airway resistance in the lungs were significantly reduced by the administration of AD4. We also found that the administration of AD4 decreased the increases of the NF-kappaB and hypoxia-inducible factor-1alpha (HIF-1alpha) levels in nuclear protein extracts of lung tissues after OVA inhalation. These results suggest that AD4 attenuates airway inflammation and hyperresponsiveness by regulating activation of NF-kappaB and HIF-1alpha as well as reducing ROS generation in allergic airway disease. PMID:18160846

  7. Noninvasive clearance of airway secretions.

    PubMed

    Hardy, K A; Anderson, B D

    1996-06-01

    or airway malacia. Use of positive pressure to maintain airway patency in these children allows cephalad clearance of secretions. Patients with segmental atelectasis, particularly related to asthma, may benefit from intrapulmonary percussive ventilator, positive expiratory pressure, or PDPV. Prevention of postoperative atelectasis is particularly well suited to positive expiratory pressure, which is not as painful as techniques using oscillations. Neurologically abnormal patients who are unable to cooperate with any active method are also treated using intrapulmonary percussive ventilator, PDPV, and suctioning, if necessary. Musculoskeletal abnormalities, muscular dystrophies, myasthenia gravis, poliomyelitis, or other similar diseases require stabilization of bellows function. Optimizing ventilation in patients with such abnormalities may require positive pressure ventilation either during sleep or continuously. Externally applied pressure, such as with the In-Exsufflator or the cyclically inflated pneumatic belt, can augment the patient's own efforts and is sometimes helpful. Normalizing the vital capacity and functional residual capacity typically helps to improve the ability to cough and clear secretions. Assisted cough devices or maneuvers are described in other papers by Bach and Hill. Not all patients who have weak muscles require nocturnal or continuous support, and may benefit from positive expiratory pressure mask treatments. Further studies are sorely needed for this population. Long-term controlled trials are urgently needed to help establish the best types of treatment for patients with CF and bronchiectasis. Such studies will become more complicated by the introduction of new treatments, such as DNase and other therapies that alter secretions, and may begin to change mucociliary or cough clearance. The selection of appropriate outcome measures is central to studying these questions, and it is unclear which are the most important. (ABSTRACT TRUNCATED

  8. Lower Extremity Muscle Activity During a Women's Overhand Lacrosse Shot.

    PubMed

    Millard, Brianna M; Mercer, John A

    2014-06-28

    The purpose of this study was to describe lower extremity muscle activity during the lacrosse shot. Participants (n=5 females, age 22±2 years, body height 162.6±15.2 cm, body mass 63.7±23.6 kg) were free from injury and had at least one year of lacrosse experience. The lead leg was instrumented with electromyography (EMG) leads to measure muscle activity of the rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and medial gastrocnemius (GA). Participants completed five trials of a warm-up speed shot (Slow) and a game speed shot (Fast). Video analysis was used to identify the discrete events defining specific movement phases. Full-wave rectified data were averaged per muscle per phase (Crank Back Minor, Crank Back Major, Stick Acceleration, Stick Deceleration). Average EMG per muscle was analyzed using a 4 (Phase) × 2 (Speed) ANOVA. BF was greater during Fast vs. Slow for all phases (p<0.05), while TA was not influenced by either Phase or Speed (p>0.05). RF and GA were each influenced by the interaction of Phase and Speed (p<0.05) with GA being greater during Fast vs. Slow shots during all phases and RF greater during Crank Back Minor and Major as well as Stick Deceleration (p<0.05) but only tended to be greater during Stick Acceleration (p=0.076) for Fast vs. Slow. The greater muscle activity (BF, RF, GA) during Fast vs. Slow shots may have been related to a faster approach speed and/or need to create a stiff lower extremity to allow for faster upper extremity movements. PMID:25114727

  9. Trunk muscle activation during golf swing: Baseline and threshold.

    PubMed

    Silva, Luís; Marta, Sérgio; Vaz, João; Fernandes, Orlando; Castro, Maria António; Pezarat-Correia, Pedro

    2013-10-01

    There is a lack of studies regarding EMG temporal analysis during dynamic and complex motor tasks, such as golf swing. The aim of this study is to analyze the EMG onset during the golf swing, by comparing two different threshold methods. Method A threshold was determined using the baseline activity recorded between two maximum voluntary contraction (MVC). Method B threshold was calculated using the mean EMG activity for 1000ms before the 500ms prior to the start of the Backswing. Two different clubs were also studied. Three-way repeated measures ANOVA was used to compare methods, muscles and clubs. Two-way mixed Intraclass Correlation Coefficient (ICC) with absolute agreement was used to determine the methods reliability. Club type usage showed no influence in onset detection. Rectus abdominis (RA) showed the higher agreement between methods. Erector spinae (ES), on the other hand, showed a very low agreement, that might be related to postural activity before the swing. External oblique (EO) is the first being activated, at 1295ms prior impact. There is a similar activation time between right and left muscles sides, although the right EO showed better agreement between methods than left side. Therefore, the algorithms usage is task- and muscle-dependent. PMID:23816264

  10. Estrus cycle effect on muscle tyrosine kinase activity in bitches.

    PubMed

    Gomes Pöppl, Álan; Costa Valle, Sandra; Hilário Díaz González, Félix; de Castro Beck, Carlos Afonso; Kucharski, Luiz Carlos; Silveira Martins Da Silva, Roselis

    2012-03-01

    Estrus cycle is a well recognized cause of insulin resistance in bitches. The insulin receptor (IR) as well as the insulin-like growth factor-I receptor belong to the same subfamily of tyrosine kinase (TK) receptors. The objective of this study was to evaluate basal TK activity in muscle tissue of bitches during the estrus cycle. Twenty-four bitches were used in the study (7 in anestrus, 7 in estrus, and 10 in diestrus). Muscle samples, taken after spaying surgery to determine TK activity, were immediately frozen in liquid nitrogen and then stored at -80°C until the membranes were prepared by sequential centrifugation after being homogenized. TK activity was determined by Poly (Glu 4:Tyr 1) phosphorylation and expressed in cpm/μg of protein. TK activity was significantly lower (P < 0.001) in the animals in estrus (104.5 ± 11.9 cpm/μg of protein) and diestrus (94.5 ± 16.9 cpm/μg of protein) when compared with bitches in anestrus (183.2 ± 39.2 cpm/μg of protein). These results demonstrate, for the first time, lower basal TK activity in the muscle tissue of female dogs during estrus and diestrus, which may represent lower insulin signaling capacity, opening a new field of investigation into the molecular mechanisms of insulin resistance in dogs. PMID:22139063

  11. Late cortical disinhibition in relaxed versus active hand muscles.

    PubMed

    Caux-Dedeystère, A; Derambure, P; Devanne, H

    2015-07-01

    Recent research suggests that long-interval intracortical inhibition (LICI) is followed by a transitory period of late cortical disinhibition (LCD) that can even lead to a net increase in cortical excitability. The relationship between LICI/LCD and voluntary drive remains poorly understood. Our study aims at investigating the influence of index abduction on LICI and LCD in an actively engaged muscle and a neighboring muscle, while varying the intensity of the conditioning stimulus (CS). Motor-evoked potentials (MEPs) were recorded from the first dorsal interosseus (FDI) and abductor digiti minimi (ADM) muscles in 13 subjects. Paired-pulses were delivered with 10 different interstimulus intervals (ranging from 60 to 290 ms). Whatever the condition (relaxed or active FDI), the test stimulus was set to evoke an MEP of 1mV. The time course of conditioned MEP amplitude was compared for relaxed and active conditions when the CS intensity was set to (i) 130% of the rest motor threshold (RMT) or (ii) to evoke the same size of MEP under both conditions. LICI lasted longer (i.e. disinhibition occurred later) at rest than during abduction when evoked either by similar or matched conditioning stimuli. No post-LICI facilitation was observed at rest - even when the CS intensity was set to 160% RMT. In contrast, long-interval intracortical facilitation (LICF) was observed in the quiescent ADM when FDI was active. LICF may then be associated with voluntary activity albeit with lack of topographic specificity. PMID:25888934

  12. Systematic review of core muscle activity during physical fitness exercises.

    PubMed

    Martuscello, Jason M; Nuzzo, James L; Ashley, Candi D; Campbell, Bill I; Orriola, John J; Mayer, John M

    2013-06-01

    A consensus has not been reached among strength and conditioning specialists regarding what physical fitness exercises are most effective to stimulate activity of the core muscles. Thus, the purpose of this article was to systematically review the literature on the electromyographic (EMG) activity of 3 core muscles (lumbar multifidus, transverse abdominis, quadratus lumborum) during physical fitness exercises in healthy adults. CINAHL, Cochrane Central Register of Controlled Trials, EMBASE, PubMed, SPORTdiscus, and Web of Science databases were searched for relevant articles using a search strategy designed by the investigators. Seventeen studies enrolling 252 participants met the review's inclusion/exclusion criteria. Physical fitness exercises were partitioned into 5 major types: traditional core, core stability, ball/device, free weight, and noncore free weight. Strength of evidence was assessed and summarized for comparisons among exercise types. The major findings of this review with moderate levels of evidence indicate that lumbar multifidus EMG activity is greater during free weight exercises compared with ball/device exercises and is similar during core stability and ball/device exercises. Transverse abdominis EMG activity is similar during core stability and ball/device exercises. No studies were uncovered for quadratus lumborum EMG activity during physical fitness exercises. The available evidence suggests that strength and conditioning specialists should focus on implementing multijoint free weight exercises, rather than core-specific exercises, to adequately train the core muscles in their athletes and clients. PMID:23542879

  13. Overexpression of Striated Muscle Activator of Rho Signaling (STARS) Increases C2C12 Skeletal Muscle Cell Differentiation

    PubMed Central

    Wallace, Marita A.; Della Gatta, Paul A.; Ahmad Mir, Bilal; Kowalski, Greg M.; Kloehn, Joachim; McConville, Malcom J.; Russell, Aaron P.; Lamon, Séverine

    2016-01-01

    Background: Skeletal muscle growth and regeneration depend on the activation of satellite cells, which leads to myocyte proliferation, differentiation and fusion with existing muscle fibers. Skeletal muscle cell proliferation and differentiation are tightly coordinated by a continuum of molecular signaling pathways. The striated muscle activator of Rho signaling (STARS) is an actin binding protein that regulates the transcription of genes involved in muscle cell growth, structure and function via the stimulation of actin polymerization and activation of serum-response factor (SRF) signaling. STARS mediates cell proliferation in smooth and cardiac muscle models; however, whether STARS overexpression enhances cell proliferation and differentiation has not been investigated in skeletal muscle cells. Results: We demonstrate for the first time that STARS overexpression enhances differentiation but not proliferation in C2C12 mouse skeletal muscle cells. Increased differentiation was associated with an increase in the gene levels of the myogenic differentiation markers Ckm, Ckmt2 and Myh4, the differentiation factor Igf2 and the myogenic regulatory factors (MRFs) Myf5 and Myf6. Exposing C2C12 cells to CCG-1423, a pharmacological inhibitor of SRF preventing the nuclear translocation of its co-factor MRTF-A, had no effect on myotube differentiation rate, suggesting that STARS regulates differentiation via a MRTF-A independent mechanism. Conclusion: These findings position STARS as an important regulator of skeletal muscle growth and regeneration. PMID:26903873

  14. The effects of inhaled corticosteroids on intrinsic responsiveness and histology of airways from infant monkeys exposed to house dust mite allergen and ozone

    SciTech Connect

    Joad, Jesse P. Kott, Kayleen S.; Bric, John M.; Schelegle, Edward S.; Gershwin, Laurel J.; Plopper, Charles G.; Peake, Janice L.; Pinkerton, Kent E.

    2008-01-15

    Inhaled corticosteroids (ICS) are recommended to treat infants with asthma, some with intermittent asthma. We previously showed that exposing infant monkeys to allergen/ozone resulted in asthma-like characteristics of their airways. We evaluated the effects of ICS on histology and intrinsic responsiveness of allergen/ozone-exposed and normal infant primate airways. Infant monkeys were exposed by inhalation to (1) filtered air and saline, (2) house dust mite allergen (HDMA) + ozone and saline, (3) filtered air and ICS (budesonide) or (4) HDMA + ozone and ICS. Allergen/ozone exposures started at 1 month and ICS at 3 months of age. At 6 months of age, methacholine-induced changes in luminal area of airways in proximal and distal lung slices were determined using videomicrometry, followed by histology of the same slices. Proximal airway responsiveness was increased by allergen/ozone and by ICS. Eosinophil profiles were increased by allergen/ozone in both proximal and distal airways, an effect that was decreased by ICS in distal airways. In both allergen/ozone- and air-exposed monkeys, ICS increased the number of alveolar attachments in distal airways, decreased mucin in proximal airways and decreased epithelial volume in both airways. ICS increased smooth muscle in air-exposed animals while decreasing it in allergen/ozone-exposed animals in both airways. In proximal airways, there was a small but significant positive correlation between smooth muscle and airway responsiveness, as well as between alveolar attachments and responsiveness. ICS change morphology and function in normal airways as well as allergen/ozone-exposed airways, suggesting that they should be reserved for infants with active symptoms.

  15. Matriptase Proteolytically Activates Influenza Virus and Promotes Multicycle Replication in the Human Airway Epithelium

    PubMed Central

    Beaulieu, Alexandre; Gravel, Émilie; Cloutier, Alexandre; Marois, Isabelle; Colombo, Éloïc; Désilets, Antoine; Verreault, Catherine; Leduc, Richard; Marsault, Éric

    2013-01-01

    Influenza viruses do not encode any proteases and must rely on host proteases for the proteolytic activation of their surface hemagglutinin proteins in order to fuse with the infected host cells. Recent progress in the understanding of human proteases responsible for influenza virus hemagglutinin activation has led to the identification of members of the type II transmembrane serine proteases TMPRSS2 and TMPRSS4 and human airway trypsin-like protease; however, none has proved to be the sole enzyme responsible for hemagglutinin cleavage. In this study, we identify and characterize matriptase as an influenza virus-activating protease capable of supporting multicycle viral replication in the human respiratory epithelium. Using confocal microscopy, we found matriptase to colocalize with hemagglutinin at the apical surface of human epithelial cells and within endosomes, and we showed that the soluble form of the protease was able to specifically cleave hemagglutinins from H1 virus, but not from H2 and H3 viruses, in a broad pH range. We showed that small interfering RNA (siRNA) knockdown of matriptase in human bronchial epithelial cells significantly blocked influenza virus replication in these cells. Lastly, we provide a selective, slow, tight-binding inhibitor of matriptase that significantly reduces viral replication (by 1.5 log) of H1N1 influenza virus, including the 2009 pandemic virus. Our study establishes a three-pronged model for the action of matriptase: activation of incoming viruses in the extracellular space in its shed form, upon viral attachment or exit in its membrane-bound and/or shed forms at the apical surface of epithelial cells, and within endosomes by its membrane-bound form where viral fusion takes place. PMID:23365447

  16. Ex Vivo Chemical Cytometric Analysis of Protein Tyrosine Phosphatase Activity in Single Human Airway Epithelial Cells

    PubMed Central

    Phillips, Ryan M.; Dailey, Lisa A.; Bair, Eric; Samet, James M.; Allbritton, Nancy L.

    2014-01-01

    We describe a novel method for the measurement of protein tyrosine phosphatase (PTP) activity in single human airway epithelial cells (hAECs) using capillary electrophoresis. This technique involved the microinjection of a fluorescent phosphopeptide that is hydrolyzed specifically by PTPs. Analyses in BEAS-2B immortalized bronchial epithelial cells showed rapid PTP-mediated dephosphorylation of the substrate (2.2 pmol min−1 mg−1) that was blocked by pretreatment of the cells with the PTP inhibitors pervanadate, Zn2+, and 1,2-naphthoquinone (76%, 69%, 100% inhibition relative to PTP activity in untreated controls, respectively). These studies were then extended to a more physiologically relevant model system: primary hAECs cultured from bronchial brushings of living human subjects. In primary hAECs, dephosphorylation of the substrate occurred at a rate of 2.2 pmol min−1 mg−1, and was also effectively inhibited by pre-incubation of the cells with the inhibitors pervanadate, Zn2+, and 1,2- naphthoquinone (91%, 88%, and 87% median PTP inhibition, respectively). Reporter proteolysis in single BEAS-2B cells occurred at a median rate of 43 fmol min−1 mg−1 resulting in a mean half-life of 20 min. The reporter displayed a similar median half-life of 28 min in these single primary cells. Finally, single viable epithelial cells (which were assayed for PTP activity immediately after collection by bronchial brushing of a human volunteer) showed dephosphorylation rates ranging from 0.34–36 pmol min−1 mg−1 (n = 6). These results demonstrate the utility and applicability of this technique for the ex vivo quantification of PTP activity in small, heterogeneous, human cells and tissues. PMID:24380370

  17. Differential Activation of Airway Eosinophils Induces IL-13 Mediated Allergic Th2 Pulmonary Responses in Mice

    PubMed Central

    Jacobsen, EA; Doyle, AD; Colbert, DC; Zellner, KR; Protheroe, CA; LeSuer, WE; Lee, NA.; Lee, JJ

    2015-01-01

    Background Eosinophils are hallmark cells of allergic Th2 respiratory inflammation. However, the relative importance of eosinophil activation and the induction of effector functions such as the expression of IL-13 to allergic Th2 pulmonary disease remain to be defined. Methods Wild type or cytokine deficient (IL-13−/− or IL-4−/−) eosinophils treated with cytokines (GM-CSF, IL-4, IL-33) were adoptively transferred into eosinophil-deficient recipient mice subjected to allergen provocation using established models of respiratory inflammation. Allergen-induced pulmonary changes were assessed. Results In contrast to the transfer of untreated blood eosinophils to the lungs of recipient eosinophildeficient mice, which induced no immune/inflammatory changes either in the lung or lung draining lymph nodes (LDLNs), pretreatment of blood eosinophils with GM-CSF prior to transfer elicited trafficking of these eosinophils to LDLNs. In turn, these LDLN eosinophils elicited the accumulation of dendritic cells and CD4+ T cells to these same LDLNs without inducing pulmonary inflammation. However, exposure of eosinophils to GM-CSF, IL-4 and IL-33 prior to transfer induced not only immune events in the LDLN, but also allergen-mediated increases in airway Th2 cytokine/chemokine levels, the subsequent accumulation of CD4+ T cells as well as alternatively activated (M2) macrophages, and the induction of pulmonary histopathologies. Significantly, this allergic respiratory inflammation was dependent on eosinophil-derived IL-13 whereas IL-4 expression by eosinophils had no significant role. Conclusion The data demonstrate the differential activation of eosinophils as a function of cytokine exposure and suggest that eosinophil-specific IL-13 expression by activated cells is a necessary component of the subsequent allergic Th2 pulmonary pathologies. PMID:26009788

  18. ARSENITE ACTIVATES KB-DEPENDENT IL-8 GENE EXPRESSION IN AIRWAY EPITHELIM IN THE ABSENCE OF NUCLEAR TRANSLOCATION OF NF-KB

    EPA Science Inventory

    Airway epithelial cells respond to certain environmental stresses by mounting a proinflammatory response, which is characterized by enhanced synthesis and release of the neutrophil chemotactic and activating factor interleukin-8 (IL-8). IL-8 expression is regulated at the transcr...

  19. A sensory neuronal ion channel essential for airway inflammation and hyperreactivity in asthma.

    PubMed

    Caceres, Ana I; Brackmann, Marian; Elia, Maxwell D; Bessac, Bret F; del Camino, Donato; D'Amours, Marc; Witek, JoAnn S; Fanger, Chistopher M; Chong, Jayhong A; Hayward, Neil J; Homer, Robert J; Cohn, Lauren; Huang, Xiaozhu; Moran, Magdalene M; Jordt, Sven-Eric

    2009-06-01

    Asthma is an inflammatory disorder caused by airway exposures to allergens and chemical irritants. Studies focusing on immune, smooth muscle, and airway epithelial function revealed many aspects of the disease mechanism of asthma. However, the limited efficacies of immune-directed therapies suggest the involvement of additional mechanisms in asthmatic airway inflammation. TRPA1 is an irritant-sensing ion channel expressed in airway chemosensory nerves. TRPA1-activating stimuli such as cigarette smoke, chlorine, aldehydes, and scents are among the most prevalent triggers of asthma. Endogenous TRPA1 agonists, including reactive oxygen species and lipid peroxidation products, are potent drivers of allergen-induced airway inflammation in asthma. Here, we examined the role of TRPA1 in allergic asthma in the murine ovalbumin model. Strikingly, genetic ablation of TRPA1 inhibited allergen-induced leukocyte infiltration in the airways, reduced cytokine and mucus production, and almost completely abolished airway hyperreactivity to contractile stimuli. This phenotype is recapitulated by treatment of wild-type mice with HC-030031, a TRPA1 antagonist. HC-030031, when administered during airway allergen challenge, inhibited eosinophil infiltration and prevented the development of airway hyperreactivity. Trpa1(-/-) mice displayed deficiencies in chemically and allergen-induced neuropeptide release in the airways, providing a potential explanation for the impaired inflammatory response. Our data suggest that TRPA1 is a key integrator of interactions between the immune and nervous systems in the airways, driving asthmatic airway inflammation following inhaled allergen challenge. TRPA1 may represent a promising pharmacological target for the treatment of asthma and other allergic inflammatory conditions. PMID:19458046

  20. Purification, characterization and activation of fish muscle prokallikrein.

    PubMed

    Richards, G P; Liang, Y M; Chao, J; Chao, L

    1997-09-01

    Fish prokallikrein was isolated and characterized from skeletal muscle of the black sea bass, Centropristis striata. The prokallikrein was purified to apparent homogeneity by anion exchange perfusion chromatography and reversed phase high performance liquid chromatography. Initial identification was by its weak immunoreactivity with human tissue kallikrein antiserum. Two-dimensional gel electrophoresis and immunoblotting identified the protein as 36 kDa with a pI of 4.95-5.15. The prokallikrein was trypsin-activated to produce an approximately 36 kDa active enzyme as identified on an SDS-polyacrylamide gel overlayed with a membrane impregnated with the fluorogenic tripeptidyl substrate D-Val-Leu-Arg-7-amino-4-trifluoromethyl-coumarin. A potential dimer at 72 kDa was also enzymatically active. Bass kallikrein cleaved low molecular weight dog kininogen to release kinin peptide as determined by radioimmunoassay. The enzyme's amidolytic activity, with a pH optimum at 9.0, was inhibited by aprotinin, benzamidine, and phenylmethanesulphonyl fluoride, but not by elastatinal, soybean trypsin inhibitor, or limabean trypsin inhibitor. Polyclonal antiserum raised against the purified bass muscle prokallikrein recognized 36 kDa and 72 kDa proteins in bass heart, skeletal muscle, spleen, swimbladder, gill, and kidney by Western blot analyses. The wide distribution of immunoreactive proteins in the tissues suggests a potential physiological role for fish kallikreins in muscle contraction and/or relaxation, the regulation of local blood flow, and in osmoregulation. The detection of fish prokallikrein and its activation leads the way for an evaluation of the impact of kallikreins in fish health and disease processes and for studying the evolution of kallikreins and related serine proteinases. PMID:9366034

  1. Episodic hypoxia evokes long-term facilitation of genioglossus muscle activity in neonatal rats

    PubMed Central

    McKay, Leanne C; Janczewski, Wiktor A; Feldman, Jack L

    2004-01-01

    The aim of this study was to determine if episodic hypoxia evokes persistent increases of genioglossus muscle (GG) activity, termed long-term facilitation (LTF), in neonatal rats in vivo. Experiments were performed on anaesthetized, spontaneously breathing, intubated neonatal rats (postnatal days (P) 3–7), divided into three groups. The first group (n = 8) was subjected to three 5-min periods of hypoxia (5% O2–95% N2) alternating with 5 min periods of room air. The second group (n = 8) was exposed to 15 min of continuous hypoxia. The third (n = 4) group was not exposed to hypoxia and served as a control. GG EMG activity and airflow were recorded before, during and for 60 min after episodic and continuous hypoxic exposure. During hypoxia, GG EMG burst amplitude and tidal volume (VT) significantly increased compared to baseline levels (episodic protocol: mean ±s.e.m.; 324 ± 59% of control and 0.13 ± 0.007 versus 0.09 ± 0.005 ml, respectively; continuous protocol: 259 ± 30% of control and 0.16 ± 0.005 versus 0.09 ± 0.007 ml, respectively; P < 0.05). After the episodic protocol, GG EMG burst amplitude transiently returned to baseline; over the next 60 min, burst amplitude progressively increased to levels significantly greater than baseline (238 ± 40% at 60 min; P < 0.05), without any significant increase in VT and respiratory frequency (P> 0.05). After the continuous protocol, there was no lasting increase in GG EMG burst amplitude. We conclude that LTF of upper airway muscles is an adaptive respiratory behaviour present from birth. PMID:15047768

  2. Development of statistical models for predicting muscle and mental activities during repetitive precision tasks.

    PubMed

    Zadry, Hilma Raimona; Dawal, Siti Zawiah Md; Taha, Zahari

    2016-09-01

    This study was conducted to develop muscle and mental activities on repetitive precision tasks. A laboratory experiment was used to address the objectives. Surface electromyography was used to measure muscle activities from eight upper limb muscles, while electroencephalography recorded mental activities from six channels. Fourteen university students participated in the study. The results show that muscle and mental activities increase for all tasks, indicating the occurrence of muscle and mental fatigue. A linear relationship between muscle activity, mental activity and time was found while subjects were performing the task. Thus, models were developed using those variables. The models were found valid after validation using other students' and workers' data. Findings from this study can contribute as a reference for future studies investigating muscle and mental activity and can be applied in industry as guidelines to manage muscle and mental fatigue, especially to manage job schedules and rotation. PMID:27053140

  3. Muscle shortening velocity depends on tissue inertia and level of activation during submaximal contractions.

    PubMed

    Ross, Stephanie A; Wakeling, James M

    2016-06-01

    In order to perform external work, muscles must do additional internal work to deform their tissue, and in particular, to overcome the inertia due to their internal mass. However, the contribution of the internal mass within a muscle to the mechanical output of that muscle has only rarely been studied. Here, we use a dynamic, multi-element Hill-type muscle model to examine the effects of the inertial mass within muscle on its contractile performance. We find that the maximum strain-rate of muscle is slower for lower activations and larger muscle sizes. As muscle size increases, the ability of the muscle to overcome its inertial load will decrease, as muscle tension is proportional to cross-sectional area and inertial load is proportional to mass. Thus, muscles that are larger in size will have a higher inertial cost to contraction. Similarly, when muscle size and inertial load are held constant, decreasing muscle activation will increase inertial cost to contraction by reducing muscle tension. These results show that inertial loads within muscle contribute to a slowing of muscle contractile velocities (strain-rates), particularly at the submaximal activations that are typical during animal locomotion. PMID:27354711

  4. Relationship between back muscle endurance and voluntary activation.

    PubMed

    Bottle, Emily; Strutton, Paul H

    2012-06-01

    There is some evidence that the Biering-Sorensen endurance test can discriminate low back pain sufferers from healthy individuals and can predict future back pain. This test relies on the subject's ability to voluntarily drive the back muscles. This neural drive, termed voluntary activation (VA) can be measured using the twitch interpolation technique. The aim of the current study was to investigate the relationship between back muscle endurance and VA. Twenty-one healthy volunteers (10 males) participated. Bilateral electromyographic recordings were obtained from erector spinae and rectus abdominis. Back extensor torque was recorded using a dynamometer. The protocol consisted of measurement of VA (using magnetic stimulation of the brain and assessment of the sizes of the evoked twitches) and measurement of endurance. There was a linear correlation (r(2)=1, P<0.01) between voluntary torque and VA. The mean (SEM) endurance time was 174.9 (12.8)s. There was no correlation between endurance and VA at either 100% MVC (r(2)=0.01, P=0.72) or at 50% MVC (r(2)=0.11, P=0.16). These findings indicate that the endurance of the back muscles, as assessed using this widely utilised test does not appear to be related to a subject's ability to drive their back muscles voluntarily either maximally or submaximally. PMID:22387330

  5. Distinct muscle apoptotic pathways are activated in muscles with different fiber types a rat model of critical illness myopathy

    PubMed Central

    Barnes, Benjamin T.; Confides, Amy L.; Rich, Mark M.; Dupont-Versteegden, Esther E.

    2015-01-01

    Critical illness myopathy (CIM) is associated with severe muscle atrophy and fatigue in affected patients. Apoptotic signaling is involved in atrophy and is elevated in muscles from patients with CIM. In this study we investigated underlying mechanisms of apoptosis-related pathways in muscles with different fiber type composition in a rat model of CIM using denervation and glucocorticoid administration (denervation and steroid-induced myopathy, DSIM). Soleus and tibialis anterior (TA) muscles showed severe muscle atrophy (40–60% of control muscle weight) and significant apoptosis in interstitial as well as myofiber nuclei that was similar between the two muscles with DSIM. Caspase-3 and −8 activities, but not caspase-9 and −12, were elevated in TA and not in soleus muscle, while the caspase-independent proteins endonuclease G (EndoG) and apoptosis inducing factor (AIF) were not changed in abundance nor differentially localized in either muscle. Anti-apoptotic proteins HSP70, −27, and apoptosis repressor with a caspase recruitment domain (ARC) were elevated in soleus compared to TA muscle and ARC was significantly decreased with induction of DSIM in soleus. Results indicate that apoptosis is a significant process associated with DSIM in both soleus and TA muscles, and that apoptosis-associated processes are differentially regulated in muscles of different function and fiber type undergoing atrophy due to DSIM. We conclude that interventions combating apoptosis with CIM may need to be directed towards inhibiting caspase-dependent as well as -independent mechanisms to be able to affect muscles of all fiber types. PMID:25740800

  6. Effects of flight speed upon muscle activity in hummingbirds.

    PubMed

    Tobalske, Bret W; Biewener, Andrew A; Warrick, Douglas R; Hedrick, Tyson L; Powers, Donald R

    2010-07-15

    Hummingbirds have the smallest body size and highest wingbeat frequencies of all flying vertebrates, so they represent one endpoint for evaluating the effects of body size on sustained muscle function and flight performance. Other bird species vary neuromuscular recruitment and contractile behavior to accomplish flight over a wide range of speeds, typically exhibiting a U-shaped curve with maxima at the slowest and fastest flight speeds. To test whether the high wingbeat frequencies and aerodynamically active upstroke of hummingbirds lead to different patterns, we flew rufous hummingbirds (Selasphorus rufus, 3 g body mass, 42 Hz wingbeat frequency) in a variable-speed wind tunnel (0-10 m s(-1)). We measured neuromuscular activity in the pectoralis (PECT) and supracoracoideus (SUPRA) muscles using electromyography (EMG, N=4 birds), and we measured changes in PECT length using sonomicrometry (N=1). Differing markedly from the pattern in other birds, PECT deactivation occurred before the start of downstroke and the SUPRA was deactivated before the start of upstroke. The relative amplitude of EMG signal in the PECT and SUPRA varied according to a U-shaped curve with flight speed; additionally, the onset of SUPRA activity became relatively later in the wingbeat at intermediate flight speeds (4 and 6 m s(-1)). Variation in the relative amplitude of EMG was comparable with that observed in other birds but the timing of muscle activity was different. These data indicate the high wingbeat frequency of hummingbirds limits the time available for flight muscle relaxation before the next half stroke of a wingbeat. Unlike in a previous study that reported single-twitch EMG signals in the PECT of hovering hummingbirds, across all flight speeds we observed 2.9+/-0.8 spikes per contraction in the PECT and 3.8+/-0.8 spikes per contraction in the SUPRA. Muscle strain in the PECT was 10.8+/-0.5%, the lowest reported for a flying bird, and average strain rate was 7.4+/-0.2 muscle

  7. Fatigue-related firing of distal muscle nociceptors reduces voluntary activation of proximal muscles of the same limb.

    PubMed

    Kennedy, David S; McNeil, Chris J; Gandevia, Simon C; Taylor, Janet L

    2014-02-15

    With fatiguing exercise, firing of group III/IV muscle afferents reduces voluntary activation and force of the exercised muscles. These afferents can also act across agonist/antagonist pairs, reducing voluntary activation and force in nonfatigued muscles. We hypothesized that maintained firing of group III/IV muscle afferents after a fatiguing adductor pollicis (AP) contraction would decrease voluntary activation and force of AP and ipsilateral elbow flexors. In two experiments (n = 10) we examined voluntary activation of AP and elbow flexors by measuring changes in superimposed twitches evoked by ulnar nerve stimulation and transcranial magnetic stimulation of the motor cortex, respectively. Inflation of a sphygmomanometer cuff after a 2-min AP maximal voluntary contraction (MVC) blocked circulation of the hand for 2 min and maintained firing of group III/IV muscle afferents. After a 2-min AP MVC, maximal AP voluntary activation was lower with than without ischemia (56.2 ± 17.7% vs. 76.3 ± 14.6%; mean ± SD; P < 0.05) as was force (40.3 ± 12.8% vs. 57.1 ± 13.8% peak MVC; P < 0.05). Likewise, after a 2-min AP MVC, elbow flexion voluntary activation was lower with than without ischemia (88.3 ± 7.5% vs. 93.6 ± 3.9%; P < 0.05) as was torque (80.2 ± 4.6% vs. 86.6 ± 1.0% peak MVC; P < 0.05). Pain during ischemia was reported as Moderate to Very Strong. Postfatigue firing of group III/IV muscle afferents from the hand decreased voluntary drive and force of AP. Moreover, this effect decreased voluntary drive and torque of proximal unfatigued muscles, the elbow flexors. Fatigue-sensitive group III/IV muscle nociceptors act to limit voluntary drive not only to fatigued muscles but also to unfatigued muscles within the same limb. PMID:24356522

  8. Adaptation of muscle gene expression to changes in contractile activity

    NASA Technical Reports Server (NTRS)

    Booth, F. W.; Babij, P.; Thomason, D. B.; Wong, T. S.; Morrison, P. R.

    1987-01-01

    A review of the existing literature regarding the effects of different types of physical activities on the gene expression of adult skeletal muscles leads us to conclude that each type of exercise training program has, as a result, a different phenotype, which means that there are multiple mechanisms, each producing a unique phenotype. A portion of the facts which support this position is presented and interpreted here. [Abstract translated from the original French by NASA].

  9. Divergent modulation of Rho‐kinase and Ca2+ influx pathways by Src family kinases and focal adhesion kinase in airway smooth muscle

    PubMed Central

    Shaifta, Yasin; Irechukwu, Nneka; Prieto‐Lloret, Jesus; MacKay, Charles E; Marchon, Keisha A; Ward, Jeremy P T

    2015-01-01

    Background and Purpose The importance of tyrosine kinases in airway smooth muscle (ASM) contraction is not fully understood. The aim of this study was to investigate the role of Src‐family kinases (SrcFK) and focal adhesion kinase (FAK) in GPCR‐mediated ASM contraction and associated signalling events. Experimental Approach Contraction was recorded in intact or α‐toxin permeabilized rat bronchioles. Phosphorylation of SrcFK, FAK, myosin light‐chain‐20 (MLC20) and myosin phosphatase targeting subunit‐1 (MYPT‐1) was evaluated in cultured human ASM cells (hASMC). [Ca2+]i was evaluated in Fura‐2 loaded hASMC. Responses to carbachol (CCh) and bradykinin (BK) and the contribution of SrcFK and FAK to these responses were determined. Key Results Contractile responses in intact bronchioles were inhibited by antagonists of SrcFK, FAK and Rho‐kinase, while after α‐toxin permeabilization, they were sensitive to inhibition of SrcFK and Rho‐kinase, but not FAK. CCh and BK increased phosphorylation of MYPT‐1 and MLC20 and auto‐phosphorylation of SrcFK and FAK. MYPT‐1 phosphorylation was sensitive to inhibition of Rho‐kinase and SrcFK, but not FAK. Contraction induced by SR Ca2+ depletion and equivalent [Ca2+]i responses in hASMC were sensitive to inhibition of both SrcFK and FAK, while depolarization‐induced contraction was sensitive to FAK inhibition only. SrcFK auto‐phosphorylation was partially FAK‐dependent, while FAK auto‐phosphorylation was SrcFK‐independent. Conclusions and Implications SrcFK mediates Ca2+‐sensitization in ASM, while SrcFK and FAK together and individually influence multiple Ca2+ influx pathways. Tyrosine phosphorylation is therefore a key upstream signalling event in ASM contraction and may be a viable target for modulating ASM tone in respiratory disease. PMID:26294392

  10. Schisandrin B inhibits the proliferation of airway smooth muscle cells via microRNA-135a suppressing the expression of transient receptor potential channel 1.

    PubMed

    Zhang, Xiao-Yu; Zhang, Luo-Xian; Guo, Ya-Li; Zhao, Li-Min; Tang, Xue-Yi; Tian, Cui-Jie; Cheng, Dong-Jun; Chen, Xian-Liang; Ma, Li-Jun; Chen, Zhuo-Chang

    2016-07-01

    Airway smooth muscle cell (ASMC) was known to involve in the pathophysiology of asthma. Schisandrin B was reported to have anti-asthmatic effects in a murine asthma model. However, the molecular mechanism involving in the effect of Schisandrin B on ASMCs remains poorly understood. Sprague-Dawley rats were divided into three groups: rats as the control (Group 1), sensitized rats (Group 2), sensitized rats and intragastric-administrated Schisandrin B (Group 3). The expression of miR-135a and TRPC1 was detected in the rats from three groups. Platelet-derived growth factor (PDGF)-BB was used to induce the proliferation of isolated ASMCs, and the expression of miR-135a and TRPC1 was detected in PDGF-BB-treated ASMCs. Cell viability was examined in ASMCs transfected with miR-135a inhibitor or si-TRPC1. The expression of TRPC1 was examined in A10 cells pretreated with miR-135a inhibitor or miR-135a mimic. In this study, we found that Schisandrin B attenuated the inspiratory and expiratory resistances in sensitized rats. Schisandrin B upregulated the mRNA level of miR-135a and decreased the expression of TRPC1 in sensitized rats. In addition, Schisandrin B reversed the expression of miR-135a and TRPC1 in PDGF-BB-induced ASMCs. Si-TRPC1 abrogated the increasing proliferation of ASMCs induced by miR-135a inhibitor. We also found that miR-135a regulated the expression of TRPC1 in the A10 cells. These results demonstrate that Schisandrin B inhibits the proliferation of ASMCs via miR-135a suppressing the expression of TRPC1. PMID:26916957

  11. Fatigue resistance of rat extraocular muscles does not depend on creatine kinase activity

    PubMed Central

    McMullen, Colleen A; Hayeß, Katrin; Andrade, Francisco H

    2005-01-01

    Background Creatine kinase (CK) links phosphocreatine, an energy storage system, to cellular ATPases. CK activity serves as a temporal and spatial buffer for ATP content, particularly in fast-twitch skeletal muscles. The extraocular muscles are notoriously fast and active, suggesting the need for efficient ATP buffering. This study tested the hypotheses that (1) CK isoform expression and activity in rat extraocular muscles would be higher, and (2) the resistance of these muscles to fatigue would depend on CK activity. Results We found that mRNA and protein levels for cytosolic and mitochondrial CK isoforms were lower in the extraocular muscles than in extensor digitorum longus (EDL). Total CK activity was correspondingly decreased in the extraocular muscles. Moreover, cytoskeletal components of the sarcomeric M line, where a fraction of CK activity is found, were downregulated in the extraocular muscles as was shown by immunocytochemistry and western blotting. CK inhibition significantly accelerated the development of fatigue in EDL muscle bundles, but had no major effect on the extraocular muscles. Searching for alternative ATP buffers that could compensate for the relative lack of CK in extraocular muscles, we determined that mRNAs for two adenylate kinase (AK) isoforms were expressed at higher levels in these muscles. Total AK activity was similar in EDL and extraocular muscles. Conclusion These data indicate that the characteristic fatigue resistance of the extraocular muscles does not depend on CK activity. PMID:16107216

  12. TCDD-Induced Activation of Aryl Hydrocarbon Receptor Inhibits Th17 Polarization and Regulates Non-Eosinophilic Airway Inflammation in Asthma

    PubMed Central

    Gu, Wen; Guo, Xue-jun

    2016-01-01

    The aryl hydrocarbon receptor (AhR), a transcription factor of the bHLH/PAS family, has recently been demonstrated to regulate T cell differentiation. Whether AhR activation participates in allergic airway inflammation remains unknown. In the current study, using a non-eosinophilic asthma model, we demonstrate that 2, 3, 7, 8-tetrachlorodibenzo-P-dioxin (TCDD), a potent AhR ligand, reduced the airway infiltration of neutrophils, airway hyperresponsiveness and Th17 cytokine expression. Furthermore, stimulation with TCDD promoted Treg differentiation and inhibited Th17 differentiation. However, the maturation of dendritic cells may not be inhibited by AhR activation. This study thus indicates a critical role of TCDD-induced AhR activation in the regulation of non-eosinophilic airway inflammation. PMID:26938767

  13. TCDD-Induced Activation of Aryl Hydrocarbon Receptor Inhibits Th17 Polarization and Regulates Non-Eosinophilic Airway Inflammation in Asthma.

    PubMed

    Li, Xiao-ming; Peng, Juan; Gu, Wen; Guo, Xue-jun

    2016-01-01

    The aryl hydrocarbon receptor (AhR), a transcription factor of the bHLH/PAS family, has recently been demonstrated to regulate T cell differentiation. Whether AhR activation participates in allergic airway inflammation remains unknown. In the current study, using a non-eosinophilic asthma model, we demonstrate that 2, 3, 7, 8-tetrachlorodibenzo-P-dioxin (TCDD), a potent AhR ligand, reduced the airway infiltration of neutrophils, airway hyperresponsiveness and Th17 cytokine expression. Furthermore, stimulation with TCDD promoted Treg differentiation and inhibited Th17 differentiation. However, the maturation of dendritic cells may not be inhibited by AhR activation. This study thus indicates a critical role of TCDD-induced AhR activation in the regulation of non-eosinophilic airway inflammation. PMID:26938767

  14. Muscle atrophy

    MedlinePlus

    Muscle wasting; Wasting; Atrophy of the muscles ... There are two types of muscle atrophy. Disuse atrophy occurs from a lack of physical activity. In most people, muscle atrophy is caused by not using the ...

  15. Activation of chloride channels in normal and cystic fibrosis airway epithelial cells by multifunctional calcium/calmodulin-dependent protein kinase

    NASA Astrophysics Data System (ADS)

    Wagner, John A.; Cozens, Alison L.; Schulman, Howard; Gruenert, Dieter C.; Stryer, Lubert; Gardner, Phyllis

    1991-02-01

    CYSTIC fibrosis is associated with defective regulation of apical membrane chloride channels in airway epithelial cells. These channels in normal cells are activated by cyclic AMP-dependent protein kinase1,2 and protein kinase C3,4. In cystic fibrosis these kinases fail to activate otherwise normal Cl- channels1-4. But Cl- flux in cystic fibrosis cells, as in normal cells, can be activated by raising intracellular Ca2+ (refs 5-10). We report here whole-cell patch clamp studies of normal and cystic fibrosis-derived airway epithelial cells showing that Cl- channel activation by Ca2+ is mediated by multifunctional Ca2+/calmodulin-dependent protein kinase. We find that intracellular application of activated kinase and ATP activates a Cl- current similar to that activated by a Ca2+ ionophore, that peptide inhibitors of either the kinase or calmodulin block Ca2+-dependent activation of Cl- channels, and that a peptide inhibitor of protein kinase C does not block Ca2+-dependent activation. Ca2+/calmodulin activation of Cl- channels presents a pathway with therapeutic potential for circumventing defective regulation of Cl- channels in cystic fibrosis.

  16. Motor activity following the silent period in human muscle

    PubMed Central

    Alston, W.; Angel, R. W.; Fink, F. S.; Hofmann, W. W.

    1967-01-01

    1. When a muscle is unloaded during voluntary contraction, there is normally a silent period in the electromyogram. The silence is terminated by a sudden return of muscle action potentials. 2. In order to investigate the mechanism of the terminal motor volley, the unloading reflex was studied in six human subjects. The independent variables were the initial muscular force, the inertia of the limb and the amount of motion permitted. The dependent variables were the size and latency of the terminal volley. 3. During isometric contraction, the amplitude of the surface-recorded muscle action potentials increased monotonically with increasing muscular tension. 4. The action potentials were significantly larger during the terminal volley than during the period before unloading. 5. When acceleration of the limb was reduced by increasing the inertia, the terminal volley was decreased in size, but the latency was not affected. 6. When movement was interrupted by a mechanical block, the latency of the terminal volley was reduced, but the size was not affected. 7. The results suggest that the terminal motor volley is not the result of a decrease in Renshaw feed-back or in autogenetic inhibition. 8. The motor volley must be regulated by proprioceptive feed-back, because it is affected by the velocity and displacement of the limb. 9. The muscle frequently responded within 20 msec after motion of the limb was blocked. Hence it appears that the mechanism involves a spinal reflex. 10. Because the motor discharge occurs while the muscle is shortening, it cannot be an ordinary stretch reflex. If the discharge is attributed to spindle afferent driving, one must assume that the gamma motor neurones are active during the silent period. 11. The authors postulate a fusimotor reflex, which is driven by afferent impulses from the moving limb and excites the alpha motoneurones by way of the `gamma loop'. PMID:6038019

  17. Proteinase activated receptor-2-mediated dual oxidase-2 up-regulation is involved in enhanced airway reactivity and inflammation in a mouse model of allergic asthma.

    PubMed

    Nadeem, Ahmed; Alharbi, Naif O; Vliagoftis, Harissios; Tyagi, Manoj; Ahmad, Sheikh F; Sayed-Ahmed, Mohamed M

    2015-07-01

    Airway epithelial cells (AECs) express a variety of receptors, which sense danger signals from various aeroallergens/pathogens being inhaled constantly. Proteinase-activated receptor 2 (PAR-2) is one such receptor and is activated by cockroach allergens, which have intrinsic serine proteinase activity. Recently, dual oxidases (DUOX), especially DUOX-2, have been shown to be involved in airway inflammation in response to Toll-like receptor activation. However, the association between PAR-2 and DUOX-2 has not been explored in airways of allergic mice. Therefore, this study investigated the contribution of DUOX-2/reactive oxygen species (ROS) signalling in airway reactivity and inflammation after PAR-2 activation. Mice were sensitized intraperitoneally with intact cockroach allergen extract (CE) in the presence of aluminium hydroxide followed by intranasal challenge with CE. Mice were then assessed for airway reactivity, inflammation, oxidative stress (DUOX-2, ROS, inducible nitric oxide synthase, nitrite, nitrotyrosine and protein carbonyls) and apoptosis (Bax, Bcl-2, caspase-3). Challenge with CE led to up-regulation of DUOX-2 and ROS in AECs with concomitant increases in airway reactivity/inflammation and parameters of oxidative stress, and apoptosis. All of these changes were significantly inhibited by intranasal administration of ENMD-1068, a small molecule antagonist of PAR-2 in allergic mice. Administration of diphenyliodonium to allergic mice also led to improvement of allergic airway responses via inhibition of the DUOX-2/ROS pathway; however, these effects were less pronounced than PAR-2 antagonism. The current study suggests that PAR-2 activation leads to up-regulation of the DUOX-2/ROS pathway in AECs, which is involved in regulation of airway reactivity and inflammation via oxidative stress and apoptosis. PMID:25684443

  18. Bile acids stimulate chloride secretion through CFTR and calcium-activated Cl- channels in Calu-3 airway epithelial cells.

    PubMed

    Hendrick, Siobhán M; Mroz, Magdalena S; Greene, Catherine M; Keely, Stephen J; Harvey, Brian J

    2014-09-01

    Bile acids resulting from the aspiration of gastroesophageal refluxate are often present in the lower airways of people with cystic fibrosis and other respiratory distress diseases. Surprisingly, there is little or no information on the modulation of airway epithelial ion transport by bile acids. The secretory effect of a variety of conjugated and unconjugated secondary bile acids was investigated in Calu-3 airway epithelial cells grown under an air-liquid interface and mounted in Ussing chambers. Electrogenic transepithelial ion transport was measured as short-circuit current (Isc). The taurine-conjugated secondary bile acid, taurodeoxycholic acid (TDCA), was found to be the most potent modulator of basal ion transport. Acute treatment (5 min) of Calu-3 cells with TDCA (25 μM) on the basolateral side caused a stimulation of Isc, and removal of extracellular Cl(-) abolished this response. TDCA produced an increase in the cystic fibrosis transmembrane conductance regulator (CFTR)-dependent current that was abolished by pretreatment with the CFTR inhibitor CFTRinh172. TDCA treatment also increased Cl(-) secretion through calcium-activated chloride (CaCC) channels and increased the Na(+)/K(+) pump current. Acute treatment with TDCA resulted in a rapid cellular influx of Ca(2+) and increased cAMP levels in Calu-3 cells. Bile acid receptor-selective activation with INT-777 revealed TGR5 localized at the basolateral membrane as the receptor involved in TDCA-induced Cl(-) secretion. In summary, we demonstrate for the first time that low concentrations of bile acids can modulate Cl(-) secretion in airway epithelial cells, and this effect is dependent on both the duration and sidedness of exposure to the bile acid. PMID:24993131

  19. Muscle spindle activity in man during voluntary fast alternating movements.

    PubMed Central

    Hagbarth, K E; Wallen, G; Löfstedt, L

    1975-01-01

    Single unit activity in primary spindle afferent nerve fibres from finger and foot flexors was recorded with tungsten microelectrodes inserted into the median and peroneal nerves of healthy subjects. During voluntary fast alternating finger and foot movements, simulating the tremor of Parkinsonism, two types of discharges were seen in the Ia afferent fibres: (1) stretch responses occurring during the flexor relaxation phases, and (2) discharges occurring during the flexor contraction phases. Contrary to the stretch responses the spindle contraction discharges could be eliminated by a partial lidocaine block of the muscle nerve proximal to the recording site, indicating that they resulted from fusimotor activation of intrafusal fibres. On the basis of the temporal relations between the beginning and end of individual EMG-bursts, the start of the spindle contraction discharges and the latency of the stretch reflex in the muscles concerned, the following conclusions were drawn: the recurrent extrafusal contractions in movements of this type are initiated by the fast direct alpha route, but individual contraction phases generally last long enough to be influenced subsequently by the coactivated fusimotor loop through the spindles. It is postulated that this gamma loop influence during alternating movements helps to keep flexor and extensor muscles working in a regular reciprocal fashion with contractions adjusted in strength to the external loads. Images PMID:125782

  20. On the Origin of Muscle Synergies: Invariant Balance in the Co-activation of Agonist and Antagonist Muscle Pairs

    PubMed Central

    Hirai, Hiroaki; Miyazaki, Fumio; Naritomi, Hiroaki; Koba, Keitaro; Oku, Takanori; Uno, Kanna; Uemura, Mitsunori; Nishi, Tomoki; Kageyama, Masayuki; Krebs, Hermano Igo

    2015-01-01

    Investigation of neural representation of movement planning has attracted the attention of neuroscientists, as it may reveal the sensorimotor transformation essential to motor control. The analysis of muscle synergies based on the activity of agonist–antagonist (AA) muscle pairs may provide insight into such transformations, especially for a reference frame in the muscle space. In this study, we examined the AA concept using the following explanatory variables: the AA ratio, which is related to the equilibrium-joint angle, and the AA sum, which is associated with joint stiffness. We formulated muscle synergies as a function of AA sums, positing that muscle synergies are composite units of mechanical impedance. The AA concept can be regarded as another form of the equilibrium-point (EP) hypothesis, and it can be extended to the concept of EP-based synergies. We introduce, here, a novel tool for analyzing the neurological and motor functions underlying human movements and review some initial insights from our results about the relationships between muscle synergies, endpoint stiffness, and virtual trajectories (time series of EP). Our results suggest that (1) muscle synergies reflect an invariant balance in the co-activation of AA muscle pairs; (2) each synergy represents the basis for the radial, tangential, and null movements of the virtual trajectory in the polar coordinates centered on the specific joint at the base of the body; and (3) the alteration of muscle synergies (for example, due to spasticity or rigidity following neurological injury) results in significant distortion of endpoint stiffness and concomitant virtual trajectories. These results indicate that muscle synergies (i.e., the balance of muscle mechanical impedance) are essential for motor control. PMID:26636079

  1. New insights into the behavior of muscle during active lengthening.

    PubMed Central

    Morgan, D L

    1990-01-01

    A muscle fiber was modeled as a series-connected string of sarcomeres, using an A. V. Hill type model for each sarcomere and allowing for some random variation in the properties of the sarcomeres. Applying stretches to this model led to the prediction that lengthening of active muscle on or beyond the plateau of the length tension curve will take place very nonuniformly, essentially by rapid, uncontrolled elongation of individual sarcomeres, one at a time, in order from the weakest toward the strongest. Such a "popped" sarcomere, at least in a single fiber, will be stretched to a length where there is no overlap between thick and thin filaments, and the tension is borne by passive components. This prediction allows modeling of many results that have previously been inexplicable, notably the permanent extra tension after stretch on the descending limb of the length tension curve, and the continued rise of tension during a continued stretch. PMID:2317547

  2. The effect of increase in baggage weight on elderly women's lower extremity muscle activation during gait.

    PubMed

    Kim, Seong-Gil; Nam, Chan-Woo; Yong, Min-Sik

    2014-01-01

    The aim of the present study was to examine the effect of increased baggage weight on the muscle activation of elderly women's lower extremities during gait. A total of 24 elderly women who were residing in communities in Daegu, South Korea aged 79.6±6.2, 149.7±7.0cm in height, and 53.5±7.2kg in weight participated in this study. The muscle activation of each muscle was measured three times at 2kg, 3kg, and 4kg of baggage weight while the subjects were conducting treadmill walking wearing backpacks. Electrodes were placed on four muscles: the quadriceps muscle (rectus femoris), the hamstring muscle (semitendinosus), the tibialis anterior muscle, and the soleus muscle. The results show that the rates of increase in muscle activation in the tibialis anterior and soleus muscles according to baggage weight increase were higher than those in the quadriceps and hamstring muscles (<0.05). These results indicate that the heavier weight loads increase the activation of muscles that control the ankle joints causing muscle fatigue. Moreover, a decrease in balance ability through muscle fatigue can be a risk factor for falls. Thus, elderly people should be instructed not to carry heavy objects. PMID:25179442

  3. The Activity of Surface Electromyographic Signal of Selected Muscles during Classic Rehabilitation Exercise

    PubMed Central

    Xiao, Jinzhuang; Sun, Jinli; Gao, Junmin; Wang, Hongrui; Yang, Xincai

    2016-01-01

    Objectives. Prone bridge, unilateral bridge, supine bridge, and bird-dog are classic rehabilitation exercises, which have been advocated as effective ways to improve core stability among healthy individuals and patients with low back pain. The aim of this study was to investigate the activity of seven selected muscles during rehabilitation exercises through the signal of surface electromyographic. Approaches. We measured the surface electromyographic signals of four lower limb muscles, two abdominal muscles, and one back muscle during rehabilitation exercises of 30 healthy students and then analyzed its activity level using the median frequency method. Results. Different levels of muscle activity during the four rehabilitation exercises were observed. The prone bridge and unilateral bridge caused the greatest muscle fatigue; however, the supine bridge generated the lowest muscle activity. There was no significant difference (P > 0.05) between left and right body side muscles in the median frequency slope during the four rehabilitation exercises of seven muscles. Conclusions. The prone bridge can affect the low back and lower limb muscles of most people. The unilateral bridge was found to stimulate muscles much more active than the supine bridge. The bird-dog does not cause much fatigue to muscles but can make most selected muscles active. PMID:27195151

  4. The Activity of Surface Electromyographic Signal of Selected Muscles during Classic Rehabilitation Exercise.

    PubMed

    Xiao, Jinzhuang; Sun, Jinli; Gao, Junmin; Wang, Hongrui; Yang, Xincai

    2016-01-01

    Objectives. Prone bridge, unilateral bridge, supine bridge, and bird-dog are classic rehabilitation exercises, which have been advocated as effective ways to improve core stability among healthy individuals and patients with low back pain. The aim of this study was to investigate the activity of seven selected muscles during rehabilitation exercises through the signal of surface electromyographic. Approaches. We measured the surface electromyographic signals of four lower limb muscles, two abdominal muscles, and one back muscle during rehabilitation exercises of 30 healthy students and then analyzed its activity level using the median frequency method. Results. Different levels of muscle activity during the four rehabilitation exercises were observed. The prone bridge and unilateral bridge caused the greatest muscle fatigue; however, the supine bridge generated the lowest muscle activity. There was no significant difference (P > 0.05) between left and right body side muscles in the median frequency slope during the four rehabilitation exercises of seven muscles. Conclusions. The prone bridge can affect the low back and lower limb muscles of most people. The unilateral bridge was found to stimulate muscles much more active than the supine bridge. The bird-dog does not cause much fatigue to muscles but can make most selected muscles active. PMID:27195151

  5. Anti-Inflammatory Effects of Levalbuterol-Induced 11β-Hydroxysteroid Dehydrogenase Type 1 Activity in Airway Epithelial Cells

    PubMed Central

    Randall, Matthew J.; Kostin, Shannon F.; Burgess, Edward J.; Hoyt, Laura R.; Ather, Jennifer L.; Lundblad, Lennart K.; Poynter, Matthew E.

    2015-01-01

    Airway epithelial NF-κB activation is observed in asthmatic subjects and is a cause of airway inflammation in mouse models of allergic asthma. Combination therapy with inhaled short-acting β2-agonists and corticosteroids significantly improves lung function and reduces inflammation in asthmatic subjects. Corticosteroids operate through a number of mechanisms to potently inhibit NF-κB activity. Since β2-agonists can induce expression of 11β-HSD1, which converts inactive 11-keto corticosteroids into active 11-hydroxy corticosteroids, thereby potentiating the effects of endogenous glucocorticoids, we examined whether this mechanism is involved in the inhibition of NF-κB activation induced by the β-agonist albuterol in airway epithelial cells. Treatment of transformed murine Club cells (MTCC) with (R)-albuterol (levalbuterol), but not with (S)- or a mixture of (R + S)- (racemic) albuterol, augmented mRNA expression of 11β-HSD1. MTCC were stably transfected with luciferase (luc) reporter constructs under transcriptional regulation by NF-κB (NF-κB/luc) or glucocorticoid response element (GRE/luc) consensus motifs. Stimulation of NF-κB/luc MTCC with lipopolysaccharide (LPS) or tumor necrosis factor-α (TNFα) induced luc activity, which was inhibited by pretreatment with (R)-, but not (S)- or racemic albuterol. Furthermore, pretreatment of GRE/luc MTCC with (R)-, but not with (S)- or racemic albuterol, augmented 11-keto corticosteroid (cortisone) induced luc activity, which was diminished by the 11β-HSD inhibitor glycyrrhetinic acid (18β-GA), indicating that there was a conversion of inactive 11-keto to active 11-hydroxy corticosteroids. LPS- and TNFα-induced NF-κB/luc activity was diminished in MTCC cells treated with a combination of cortisone and (R)-albuterol, an effect that was inhibited by 18β-GA. Finally, pretreatment of MTCC cells with the combination of cortisone and (R)-albuterol diminished LPS- and TNFα-induced pro-inflammatory cytokine

  6. Anti-inflammatory effects of levalbuterol-induced 11β-hydroxysteroid dehydrogenase type 1 activity in airway epithelial cells.

    PubMed

    Randall, Matthew J; Kostin, Shannon F; Burgess, Edward J; Hoyt, Laura R; Ather, Jennifer L; Lundblad, Lennart K; Poynter, Matthew E

    2014-01-01

    Airway epithelial NF-κB activation is observed in asthmatic subjects and is a cause of airway inflammation in mouse models of allergic asthma. Combination therapy with inhaled short-acting β2-agonists and corticosteroids significantly improves lung function and reduces inflammation in asthmatic subjects. Corticosteroids operate through a number of mechanisms to potently inhibit NF-κB activity. Since β2-agonists can induce expression of 11β-HSD1, which converts inactive 11-keto corticosteroids into active 11-hydroxy corticosteroids, thereby potentiating the effects of endogenous glucocorticoids, we examined whether this mechanism is involved in the inhibition of NF-κB activation induced by the β-agonist albuterol in airway epithelial cells. Treatment of transformed murine Club cells (MTCC) with (R)-albuterol (levalbuterol), but not with (S)- or a mixture of (R + S)- (racemic) albuterol, augmented mRNA expression of 11β-HSD1. MTCC were stably transfected with luciferase (luc) reporter constructs under transcriptional regulation by NF-κB (NF-κB/luc) or glucocorticoid response element (GRE/luc) consensus motifs. Stimulation of NF-κB/luc MTCC with lipopolysaccharide (LPS) or tumor necrosis factor-α (TNFα) induced luc activity, which was inhibited by pretreatment with (R)-, but not (S)- or racemic albuterol. Furthermore, pretreatment of GRE/luc MTCC with (R)-, but not with (S)- or racemic albuterol, augmented 11-keto corticosteroid (cortisone) induced luc activity, which was diminished by the 11β-HSD inhibitor glycyrrhetinic acid (18β-GA), indicating that there was a conversion of inactive 11-keto to active 11-hydroxy corticosteroids. LPS- and TNFα-induced NF-κB/luc activity was diminished in MTCC cells treated with a combination of cortisone and (R)-albuterol, an effect that was inhibited by 18β-GA. Finally, pretreatment of MTCC cells with the combination of cortisone and (R)-albuterol diminished LPS- and TNFα-induced pro-inflammatory cytokine

  7. Muscle activity-torque-velocity relations in human elbow extensor muscles.

    PubMed

    Uchiyama, T; Akazawa, K

    1999-01-01

    With the aid of an artificial neural network technique, we investigated relationships between the torque and extending velocity of an elbow at constant muscle activation in healthy volunteers. Each subject sat on a chair and was able to move his upper- and forearm on a shoulder-high horizontal plane. First, with the gravitational force of a weight hanging from a pulley, the subject's wrist was pulled to flex the elbow. Next, the subject was instructed to extend his elbow joint at a constant velocity. Integrated electromyograms (IEMGs), elbow joint angle and torque were measured while the elbow was being extending. Then the relationships among these three variables were modeled using an artificial neural network where IEMGs, joint angle and velocity were the inputs, and torque was the output. After back propagation learning, we presented various combinations of IEMGs, elbow joint angle and velocity to the model, and estimated the elbow joint torque to obtain the torque-velocity relationship for constant muscle activation. The torque decreased in a nearly linear manner as the velocity increased. This was caused by slow extending velocity and was explained by Hill's equation at slow velocity. PMID:10718668

  8. Muscle-Strengthening Activities and Participation among Adults in the United States

    ERIC Educational Resources Information Center

    Loustalot, Fleetwood; Carlson, Susan A.; Kruger, Judy; Buchner, David M.; Fulton, Janet E.

    2013-01-01

    Purpose: To describe those who reported meeting the "2008 Physical Activity Guidelines for Americans" ("2008 Guidelines") muscle-strengthening standard of 2 or more days per week, including all seven muscle groups, and to assess the type and location of muscle-strengthening activities performed. Method: Data from HealthStyles…

  9. Dark/light transition and vigilance states modulate jaw-closing muscle activity level in mice.

    PubMed

    Katayama, Keisuke; Mochizuki, Ayako; Kato, Takafumi; Ikeda, Minako; Ikawa, Yasuha; Nakamura, Shiro; Nakayama, Kiyomi; Wakabayashi, Noriyuki; Baba, Kazuyoshi; Inoue, Tomio

    2015-12-01

    Bruxism is associated with an increase in the activity of the jaw-closing muscles during sleep and wakefulness. However, the changes in jaw-closing muscle activity across states of vigilance over a 24-h period are unclear. In this study, we investigated the effects of dark/light transition and sleep/wake state on EMG activity of the masseter (jaw-closing) muscle in comparison with the activity of the upper trapezius muscle (a neck muscle) over a 24-h period in mice. The activities of the masseter and neck muscles during wakefulness were much greater than during non-REM and REM sleep. In contrast, the activities of both muscles slightly, but significantly, decreased during the transition period from dark to light. Histograms of masseter activity during wakefulness and non-REM sleep showed bimodal distributions, whereas the neck muscle showed unimodal activation in all states. These results suggest that the activities of jaw-closing and neck muscles are modulated by both sleep/wake state and dark/light transition, with the latter being to a lesser degree. Furthermore, even during non-REM sleep, jaw-closing muscles display bimodal activation, which may contribute to the occurrence of exaggerated aberrant muscle activity, such as sleep bruxism. PMID:26188127

  10. Cerebellar brain inhibition in the target and surround muscles during voluntary tonic activation.

    PubMed

    Panyakaew, Pattamon; Cho, Hyun Joo; Srivanitchapoom, Prachaya; Popa, Traian; Wu, Tianxia; Hallett, Mark

    2016-04-01

    Motor surround inhibition is the neural mechanism that selectively favours the contraction of target muscles and inhibits nearby muscles to prevent unwanted movements. This inhibition was previously reported at the onset of a movement, but not during a tonic contraction. Cerebellar brain inhibition (CBI) is reduced in active muscles during tonic activation; however, it has not been studied in the surround muscles. CBI was evaluated in the first dorsal interosseus (FDI) muscle as the target muscle, and the abductor digiti minimi, flexor carpi radialis and extensor carpi radialis muscles as surround muscles, during rest and tonic activation of the FDI muscle in 21 subjects. Cerebellar stimulation was performed under magnetic resonance imaging-guided neuronavigation targeting lobule VIII of the cerebellar hemisphere. Stimulus intensities for cerebellar stimulation were based on the resting motor cortex threshold (RMT) and adjusted for the depth difference between the cerebellar and motor cortices. We used 90-120% of the adjusted RMT as the conditioning stimulus intensity during rest. The intensity that generated the best CBI at rest in the FDI muscle was selected for use during tonic activation. During selective tonic activation of the FDI muscle, CBI was significantly reduced only for the FDI muscle, and not for the surround muscles. Unconditioned motor evoked potential sizes were increased in all muscles during FDI muscle tonic activation as compared with rest, despite background electromyography activity increasing only for the FDI muscle. Our study suggests that the cerebellum may play an important role in selective tonic finger movement by reducing its inhibition in the motor cortex only for the relevant agonist muscle. PMID:26900871

  11. Arylhydrocarbon receptor (AhR) activation in airway epithelial cells induces MUC5AC via reactive oxygen species (ROS) production.

    PubMed

    Chiba, Takahito; Uchi, Hiroshi; Tsuji, Gaku; Gondo, Hisaki; Moroi, Yoichi; Furue, Masutaka

    2011-02-01

    The dioxins and dioxin-like compounds in cigarette smoke regulate various immunological responses via the arylhydrocarbon receptor (AhR). These environmental toxicants are known to cause bronchitis, asthma, chronic obstructive pulmonary disease (COPD), and lung cancer. Recent studies have demonstrated that AhR activation upregulates the expression of mucin 5AC, oligomeric mucus/gel-forming (MUC5AC) in the airway epithelial cell line. However, the mechanism for the production of mucin has not been clarified. In this study, we investigated the role and pathway of AhR in airway epithelial cells by using selective agonists and antagonists. After stimulation with or without benzopyrene (B[a]P), an AhR agonist, MUC5AC expression was measured by real-time RT-PCR. The mechanism of AhR-induced MUC5AC expression in airway epithelial cells was studied in terms of the production of cytokine and reactive oxygen species (ROS). Treatment with B[a]P increased ROS generation in NCI-H₂₉₂ cells. Furthermore, B[a]P-induced MUC5AC upregulation and mucin production were inhibited by AhR siRNA or the use of an antioxidative agent. These results suggest that the AhR-induced increase of mucin production is partially mediated by ROS generation. An antioxidant therapy approach may help to cure AhR-induced mucus hypersecretory diseases. PMID:20709182

  12. Mitochondrial N-formyl peptides cause airway contraction and lung neutrophil infiltration via formyl peptide receptor activation.

    PubMed

    Wenceslau, Camilla Ferreira; Szasz, Theodora; McCarthy, Cameron G; Baban, Babak; NeSmith, Elizabeth; Webb, R Clinton

    2016-04-01

    Respiratory failure is a common characteristic of systemic inflammatory response syndrome (SIRS) and sepsis. Trauma and severe blood loss cause the release of endogenous molecules known as damage-associated molecular patterns (DAMPs). Mitochondrial N-formyl peptides (F-MITs) are DAMPs that share similarities with bacterial N-formylated peptides, and are potent immune system activators. Recently, we observed that hemorrhagic shock-induced increases in plasma levels of F-MITs associated with lung damage, and that antagonism of formyl peptide receptors (FPR) ameliorated hemorrhagic shock-induced lung injury in rats. Corroborating these data, in the present study, it was observed that F-MITs expression is higher in plasma samples from trauma patients with SIRS or sepsis when compared to control trauma group. Therefore, to better understand the role of F-MITs in the regulation of lung and airway function, we studied the hypothesis that F-MITs lead to airway contraction and lung inflammation. We observed that F-MITs induced concentration-dependent contraction in trachea, bronchi and bronchioles. However, pre-treatment with mast cells degranulator or FPR antagonist decreased this response. Finally, intratracheal challenge with F-MITs increased neutrophil elastase expression in lung and inducible nitric oxide synthase and cell division control protein 42 expression in all airway segments. These data suggest that F-MITs could be a putative target to treat respiratory failure in trauma patients. PMID:26923940

  13. Glutathione Reaction Products with a Chemical Allergen, Methylene-diphenyl Diisocyanate, Stimulate Alternative Macrophage Activation and Eosinophilic Airway Inflammation

    PubMed Central

    Wisnewski, Adam V.; Liu, Jian; Colangelo, Christopher M.

    2015-01-01

    Isocyanates have been a leading chemical cause of occupational asthma since their utility for generating polyurethane was first recognized over 60 years ago, yet the mechanisms of isocyanate asthma pathogenesis remain unclear. The present study provides in vivo evidence that a GSH mediated pathway underlies asthma-like eosinophilic inflammatory responses to respiratory tract isocyanate exposure. In naïve mice, a mixture of GSH reaction products with the chemical allergen, methylene-diphenyl diisocyanate (MDI), induced innate immune responses, characterized by significantly increased airway levels of Chitinase YM-1 and IL-12/IL-23β (but not α) subunit. However, in mice immunologically sensitized to MDI via prior skin exposure, identical GSH–MDI doses induced substantially greater inflammatory responses, including significantly increased airway eosinophil numbers and mucus production, along with IL-12/IL-23β, chitinases, and other indicators of alternative macrophage activation. The “self”-protein albumin in mouse airway fluid was uniquely modified by GSH–MDI at position 414K, a preferred site of MDI reactivity on human albumin. The 414K–MDI conjugation appears to covalently cross-link GSH to albumin via GSH's NH2-terminus, a unique conformation possibly resulting from cyclized mono(GSH)–MDI or asymmetric (S,N′-linked) bis(GSH)–MDI conjugates. Together, the data support a possible thiol mediated transcarbamoylating mechanism linking MDI exposure to pathogenic eosinophilic inflammatory responses. PMID:25635619

  14. Cholinergic activation of the murine trachealis muscle via non-vesicular acetylcholine release involving low-affinity choline transporters.

    PubMed

    Nassenstein, Christina; Wiegand, Silke; Lips, Katrin S; Li, Guanfeng; Klein, Jochen; Kummer, Wolfgang

    2015-11-01

    In addition to quantal, vesicular release of acetylcholine (ACh), there is also non-quantal release at the motor endplate which is insufficient to evoke postsynaptic responses unless acetylcholinesterase (AChE) is inhibited. We here addressed potential non-quantal release in the mouse trachea by organ bath experiments and (immuno)histochemical methods. Electrical field stimulation (EFS) of nerve terminals elicited tracheal constriction that is largely due to ACh release. Classical enzyme histochemistry demonstrated acetylcholinesterase (AChE) activity in nerve fibers in the muscle and butyrylcholinesterase (BChE) activity in the smooth muscle cells. Acute inhibition of both esterases by eserine significantly raised tracheal tone which was fully sensitive to atropine. This effect was reduced, but not abolished, in AChE, but not in BChE gene-deficient mice. The eserine-induced increase in tracheal tone was unaffected by vesamicol (10(-5)M), an inhibitor of the vesicular acetylcholine transporter, and by corticosterone (10(-4)M), an inhibitor of organic cation transporters. Hemicholinium-3, in low concentrations an inhibitor of the high-affinity choline transporter-1 (CHT1), completely abrogated the eserine effects when applied in high concentrations (10(-4)M) pointing towards an involvement of low-affinity choline transporters. To evaluate the cellular sources of non-quantal ACh release in the trachea, expression of low-affinity choline transporter-like family (CTL1-5) was evaluated by RT-PCR analysis. Even though these transporters were largely abundant in the epithelium, denudation of airway epithelial cells had no effect on eserine-induced tracheal contraction, indicating a non-quantal release of ACh from non-epithelial sources in the airways. These data provide evidence for an epithelium-independent non-vesicular, non-quantal ACh release in the mouse trachea involving low-affinity choline transporters. PMID:26278668

  15. Inward spread of activation in vertebrate muscle fibres

    PubMed Central

    González-Serratos, H.

    1971-01-01

    1. A method for detecting the activation of individual myofibrils or groups of myofibrils within an isolated muscle fibre is described. It consists in making all the myofibrils wavy by setting the fibre in gelatine and compressing it longitudinally; active shortening of myofibrils can then be recognized by the straightening out of the waves. 2. The time course of this straightening during a twitch was found by high-speed ciné micrography. 3. There is a delay of activation between the superficial and central myofibrils, from which the velocity of inward spread of activation can be found. 4. This velocity has a Q10 of 2, and is about 7 cm/sec at 20° C. The mechanism of the inward spread of activation is discussed. 5. On relaxation the waves reappear, showing that there is a spontaneous elongation of the myofibrils. ImagesPlate 1Plate 2Plate 3Plate 4 PMID:5557071

  16. Activities of potassium and sodium ions in rabbit heart muscle.

    PubMed

    Lee, C O; Fozzard, H A

    1975-06-01

    Activities (a) of intracellular K and Na in rabbit ventricular papillary muslces were determined with cation-selectivve glass microelectrodes and concentrations (C) were estimated with flame photometry. The CK and aK of the muscles were 134.9 +/- 3.1 mM (mean value +/- SE) and 82.6 mM, respectively, at 25 degrees C. The corresponding CNa and aNa were 32.7 +/- 2.7 and 5.7, respectively. The apparent intracellular activity coefficients for K (gammaK) and Na (gammaNa) were 0.612 and 0.175, respectively. Similar results were obtained at 35 +/- 1 degree C. gammaK was substantially lower than the activity coefficient (0.745) of extracellular fluid (Tyrode's solution), which might be expected on the basis of a different intracellular ionic strength. gammaNa was much lower than that of extracellular fluid, and suggest that much of the Na was compartmentalized or sequestered. For external K concentrations greater than 5 mM, the resting membrane potentials agreed well with the potential differences calculated from the K activity gradients across the cell membrane as a potassium electrode. These results emphasize that potassium equilibrium potentials in heart muscle should be calculated by activities rather than concentrations. PMID:1194884

  17. Activities of potassium and sodium ions in rabbit heart muscle

    PubMed Central

    1975-01-01

    Activities (a) of intracellular K and Na in rabbit ventricular papillary muslces were determined with cation-selectivve glass microelectrodes and concentrations (C) were estimated with flame photometry. The CK and aK of the muscles were 134.9 +/- 3.1 mM (mean value +/- SE) and 82.6 mM, respectively, at 25 degrees C. The corresponding CNa and aNa were 32.7 +/- 2.7 and 5.7, respectively. The apparent intracellular activity coefficients for K (gammaK) and Na (gammaNa) were 0.612 and 0.175, respectively. Similar results were obtained at 35 +/- 1 degree C. gammaK was substantially lower than the activity coefficient (0.745) of extracellular fluid (Tyrode's solution), which might be expected on the basis of a different intracellular ionic strength. gammaNa was much lower than that of extracellular fluid, and suggest that much of the Na was compartmentalized or sequestered. For external K concentrations greater than 5 mM, the resting membrane potentials agreed well with the potential differences calculated from the K activity gradients across the cell membrane as a potassium electrode. These results emphasize that potassium equilibrium potentials in heart muscle should be calculated by activities rather than concentrations. PMID:1194884

  18. Chronic Assessment of Diaphragm Muscle EMG Activity across Motor Behaviors

    PubMed Central

    Mantilla, Carlos B.; Seven, Yasin B.; Hurtado-Palomino, Juan N.; Zhan, Wen-Zhi; Sieck, Gary C.

    2011-01-01

    The diaphragm muscle is main inspiratory muscle in mammals. Quantitative analyses documenting the reliability of chronic diaphragm EMG recordings are lacking. Assessment of ventilatory and non-ventilatory motor behaviors may facilitate evaluating diaphragm EMG activity over time. We hypothesized that normalization of diaphragm EMG amplitude across behaviors provides stable and reliable parameters for longitudinal assessments of diaphragm activity. We found that diaphragm EMG activity shows substantial intra-animal variability over 6 weeks, with coefficient of variation (CV) for different behaviors ~29–42%. Normalization of diaphragm EMG activity to near maximal behaviors (e.g., deep breathing) reduced intra-animal variability over time (CV ~22–29%). Plethysmographic measurements of eupneic ventilation were also stable over 6 weeks (CV ~13% for minute ventilation). Thus, stable and reliable measurements of diaphragm EMG activity can be obtained longitudinally using chronically implanted electrodes by examining multiple motor behaviors. By quantitatively determining the reliability of longitudinal diaphragm EMG analyses, we provide an important tool for evaluating the progression of diseases or injuries that impair ventilation. PMID:21414423

  19. Role of Central Neurotransmission and Chemoreception on Airway Control

    PubMed Central

    Kc, Prabha; Martin, Richard J.

    2010-01-01

    This review summarizes work on central neurotransmission, chemoreception and CNS control of cholinergic outflow to the airways. First, we describe the neural transmission of bronchoconstrictive signals from airway afferents to the airway-related vagal preganglionic neurons (AVPNs) via the nucleus of the solitary tract (nTS) and, second, we characterize evidence for a modulatory effect of excitatory glutamatergic, and inhibitory GABAergic, noradrenergic and serotonergic pathways on AVPN output. Excitatory signals arising from bronchopulmonary afferents and/or the peripheral chemosensory system activate second order neurons within the nTS, via a glutamate-AMPA (alpha-amino-3- hydroxy-5-methyl-4-isoxazolepropionic acid) receptor signaling pathway. These nTS neurons, using the same neurotransmitter-receptor unit, transmit information to the AVPNs, which in turn convey the central command through descending fibers and airway intramural ganglia to airway smooth muscle, submucosal secretory glands, and the vasculature. The strength and duration of this reflex-induced bronchoconstriction is modulated by GABAergic-inhibitory inputs. In addition, central noradrenergic and serotonergic inhibitory pathways appear to participate in the regulation of cholinergic drive to the tracheobronchial system. Down-regulation of these inhibitory influences results in a shift from inhibitory to excitatory drive, which may lead to increased excitability of AVPNs, heightened airway responsiveness, greater cholinergic outflow to the airways and consequently bronchoconstriction. In summary, centrally coordinated control of airway tone and respiratory drive serve to optimize gas exchange and work of breathing under normal homeostatic conditions. Greater understanding of this process should enhance our understanding of its disruption under pathophysiologic states. PMID:20359553

  20. Understanding compensatory strategies for muscle weakness during gait by simulating activation deficits seen post-stroke

    PubMed Central

    Knarr, Brian A.; Reisman, Darcy S.; Binder-Macleod, Stuart A.; Higginson, Jill S.

    2012-01-01

    Musculoskeletal simulations have been used to explore compensatory strategies, but have focused on responses to simulated atrophy in a single muscle or muscle group. In a population such as stroke, however, impairments are seen in muscle activation across multiple muscle groups. The objective of this study was to identify available compensatory strategies for muscle weakness during gait by simulating activation deficits in multiple muscle groups. Three dimensional dynamics simulations were created from 10 healthy subjects (48.8±13.3yrs, self-selected speed 1.28±0.17m/s) and constraints were set on the activation capacity of the plantar flexor, dorsiflexor, and hamstrings muscle groups to simulate activation impairments seen post stroke. When the muscle groups are impaired individually, the model requires that the plantar flexor, dorsiflexor, and hamstrings muscle groups are activated to at least 55%, 64%, and 18%, respectively, to recreate the subjects’ normal gait pattern. The models were unable to recreate the normal gait pattern with simultaneous impairment of all three muscle groups. Other muscle groups are unable to assist the dorsiflexor muscles during early swing, which suggests that rehabilitation or assistive devices may be required to correct foot drop. By identifying how muscles can interact, clinicians may be able to develop specific strategies for using gait retraining and orthotic assistance to best address an individual’s needs. PMID:23273489

  1. The effects of shoulder joint abduction angles on the muscle activity of the serratus anterior muscle and the upper trapezius muscle while vibrations are applied

    PubMed Central

    Jung, Da-eun; Moon, Dong-chul

    2015-01-01

    [Purpose] The purpose of this study was to examine the ratio between the upper trapezius and the serratus anterior muscles during diverse shoulder abduction exercises applied with vibrations in order to determine the appropriate exercise methods for recovery of scapular muscle balance. [Subjects and Methods] Twenty-four subjects voluntarily participated in this study. The subjects performed shoulder abduction at various shoulder joint abduction angles (90°, 120°, 150°, 180°) with oscillation movements. [Results] At 120°, all the subjects showed significant increases in the muscle activity of the serratus anterior muscle in comparison with the upper trapezius muscle. However, no significant difference was found at angles other than 120°. [Conclusion] To selectively strengthen the serratus anterior, applying vibration stimuli at the 120° shoulder abduction position is considered to be appropriate. PMID:25642052

  2. Aldehyde dehydrogenase activity promotes survival of human muscle precursor cells

    PubMed Central

    Jean, Elise; Laoudj-Chenivesse, Dalila; Notarnicola, Cécile; Rouger, Karl; Serratrice, Nicolas; Bonnieu, Anne; Gay, Stéphanie; Bacou, Francis; Duret, Cédric; Carnac, Gilles

    2011-01-01

    Abstract Aldehyde dehydrogenases (ALDH) are a family of enzymes that efficiently detoxify aldehydic products generated by reactive oxygen species and might therefore participate in cell survival. Because ALDH activity has been used to identify normal and malignant cells with stem cell properties, we asked whether human myogenic precursor cells (myoblasts) could be identified and isolated based on their levels of ALDH activity. Human muscle explant-derived cells were incubated with ALDEFLUOR, a fluorescent substrate for ALDH, and we determined by flow cytometry the level of enzyme activity. We found that ALDH activity positively correlated with the myoblast-CD56+ fraction in those cells, but, we also observed heterogeneity of ALDH activity levels within CD56-purified myoblasts. Using lentiviral mediated expression of shRNA we demonstrated that ALDH activity was associated with expression of Aldh1a1 protein. Surprisingly, ALDH activity and Aldh1a1 expression levels were very low in mouse, rat, rabbit and non-human primate myoblasts. Using different approaches, from pharmacological inhibition of ALDH activity by diethylaminobenzaldehyde, an inhibitor of class I ALDH, to cell fractionation by flow cytometry using the ALDEFLUOR assay, we characterized human myoblasts expressing low or high levels of ALDH. We correlated high ALDH activity ex vivo to resistance to hydrogen peroxide (H2O2)-induced cytotoxic effect and in vivo to improved cell viability when human myoblasts were transplanted into host muscle of immune deficient scid mice. Therefore detection of ALDH activity, as a purification strategy, could allow non-toxic and efficient isolation of a fraction of human myoblasts resistant to cytotoxic damage. PMID:19840193

  3. DIESEL EXHAUST ACTIVATES REDOX-SENSITIVE TRANSCRIPTION FACTORS AND KINASES IN HUMAN AIRWAYS

    EPA Science Inventory

    Diesel exhaust (DE) is a major component of airborne particulate matter. In previous studies we have described the acute inflammatory response of the human airway to inhaled DE. This was characterized by neutrophil, mast cell, and lymphocyte infiltration into the bronchial mucosa...

  4. Direct optical activation of skeletal muscle fibres efficiently controls muscle contraction and attenuates denervation atrophy

    PubMed Central

    Magown, Philippe; Shettar, Basavaraj; Zhang, Ying; Rafuse, Victor F.

    2015-01-01

    Neural prostheses can restore meaningful function to paralysed muscles by electrically stimulating innervating motor axons, but fail when muscles are completely denervated, as seen in amyotrophic lateral sclerosis, or after a peripheral nerve or spinal cord injury. Here we show that channelrhodopsin-2 is expressed within the sarcolemma and T-tubules of skeletal muscle fibres in transgenic mice. This expression pattern allows for optical control of muscle contraction with comparable forces to nerve stimulation. Force can be controlled by varying light pulse intensity, duration or frequency. Light-stimulated muscle fibres depolarize proportionally to light intensity and duration. Denervated triceps surae muscles transcutaneously stimulated optically on a daily basis for 10 days show a significant attenuation in atrophy resulting in significantly greater contractile forces compared with chronically denervated muscles. Together, this study shows that channelrhodopsin-2/H134R can be used to restore function to permanently denervated muscles and reduce pathophysiological changes associated with denervation pathologies. PMID:26460719

  5. Systems-level airway models of bronchoconstriction.

    PubMed

    Donovan, Graham M

    2016-09-01

    Understanding lung and airway behavior presents a number of challenges, both experimental and theoretical, but the potential rewards are great in terms of both potential treatments for disease and interesting biophysical phenomena. This presents an opportunity for modeling to contribute to greater understanding, and here, we focus on modeling efforts that work toward understanding the behavior of airways in vivo, with an emphasis on asthma. We look particularly at those models that address not just isolated airways but many of the important ways in which airways are coupled both with each other and with other structures. This includes both interesting phenomena involving the airways and the layer of airway smooth muscle that surrounds them, and also the emergence of spatial ventilation patterns via dynamic airway interaction. WIREs Syst Biol Med 2016, 8:459-467. doi: 10.1002/wsbm.1349 For further resources related to this article, please visit the WIREs website. PMID:27348217

  6. Gluteus medius and scapula muscle activations in youth baseball pitchers.

    PubMed

    Oliver, Gretchen D; Weimar, Wendi H; Plummer, Hillary A

    2015-06-01

    The baseball pitching motion is a total kinetic chain activity that must efficiently use both the upper and lower extremity. Of particular importance is the scapular motion, which is critical for humeral positioning and proper alignment of shoulder musculature. It was hypothesized that scapular stability is enhanced by pelvic girdle stability. Therefore, it was the purpose of this study to determine the muscle activations of selected pelvic and scapular stabilizing muscles during a fastball pitch in youth baseball pitchers. Twenty youth baseball pitchers (age: 11.3 + 1.0 years; height: 152.4 + 9.0 cm; weight: 47.5 + 11.3 kg) were recorded throwing 4-seam fastballs for strikes. Data revealed moderate (20-39% maximum voluntary isometric contraction [MVIC]) to moderately strong (>40% MVIC) activation of the ipsilateral (throwing arm side) gluteus medius, upper trapezius, and serratus anterior throughout phases 2 (maximum shoulder external rotation to ball release) and 3 (ball release to maximum shoulder internal rotation). Moderately strong activation (>40% MVIC) of the upper trapezius and serratus anterior was noted during phases 2 and 3 of the pitching motion. Pearson's product-moment correlation revealed significant relationships between bilateral gluteus medius and the force couples about the scapula during all 3 phases of the pitching motion. The results of this study provide important data that improve the understanding of the muscular relationship between the pelvic and scapular stabilizers during the fastball pitch. Training and rehabilitation programs should consider focusing on lumbopelvic-hip and scapular muscle strengthening as well as coordinated strengthening of the pelvic and scapular stabilizers, in baseball pitchers. PMID:25546449

  7. Airway tissue factor-dependent coagulation activity in response to sulfur mustard analog 2-chloroethyl ethyl sulfide

    PubMed Central

    Rancourt, Raymond C.; Veress, Livia A.; Guo, XiaoLing; Jones, Tara N.; Hendry-Hofer, Tara B.

    2012-01-01

    Acute lung injury is a principal cause of morbidity and mortality in response to mustard gas (SM) inhalation. Obstructive, fibrin-containing airway casts have recently been reported in a rat inhalation model employing the SM analog 2-chloroethyl ethyl sulfide (CEES). The present study was designed to identify the mechanism(s) causing activation of the coagulation cascade after CEES-induced airway injury. Here we report that CEES inhalation elevates tissue factor (TF) activity and numbers of detached epithelial cells present in lavage fluid (BALF) from rats after exposure (18 h). In vitro studies using 16HBE cells, or with rat BALF, indicated that detached epithelial cells could convert factor X (FX) to the active form FXa when incubated with factor VII and could elicit rapid clotting of plasma. In addition, immunocytochemical analysis demonstrated elevated cell surface (TF) expression on CEES-exposed 16HBE cells as a function of time. However, total cell TF expression did not increase. Since membrane surfaces bearing TF are important determinants of clot initiation, anticoagulants directed against these entities were tested for ability to limit plasma clotting or FX activation capacity of BALF or culture media. Addition of tifacogin, a TF pathway inhibitor, effectively blocked either activity, demonstrating that the procoagulant actions of CEES were TF pathway dependent. Lactadherin, a protein capable of competing with clotting factors for phospholipid-binding sites, was partially effective in limiting these procoagulant actions. These findings indicate that TF pathway inhibition could be an effective strategy to prevent airway obstruction after SM or CEES inhalation. PMID:21964405

  8. Lumbar spinal loads and muscle activity during a golf swing.

    PubMed

    Lim, Young-Tae; Chow, John W; Chae, Woen-Sik

    2012-06-01

    This study estimated the lumbar spinal loads at the L4-L5 level and evaluated electromyographic (EMG) activity of right and left rectus abdominis, external and internal obliques, erector spinae, and latissimus dorsi muscles during a golf swing. Four super VHS camcorders and two force plates were used to obtain three-dimensional (3D) kinematics and kinetics of golf swings performed by five male collegiate golfers. Average EMG levels for different phases of golf swing were determined. An EMG-assisted optimization model was applied to compute the contact forces acting on the L4-L5. The results revealed a mean peak compressive load of over six times the body weight (BW) during the downswing and mean peak anterior and medial shear loads approaching 1.6 and 0.6 BW during the follow-through phases. The peak compressive load estimated in this study was high, but less than the corresponding value (over 8 BW) reported by a previous study. Average EMG levels of different muscles were the highest in the acceleration and follow-through phases, suggesting a likely link between co-contractions of paraspinal muscles and lumbar spinal loads. PMID:22900401

  9. Diabetic state-induced activation of calcium-activated neutral proteinase in mouse skeletal muscle.

    PubMed

    Kobayashi, S; Fujihara, M; Hoshino, N; Kimura, I; Kimura, M

    1989-12-01

    The effect of a diabetic state in the diabetic KK-CAy mouse on calcium activated neutral proteinase (CANP) of hind-limb skeletal muscles was investigated. In the diabetic state, there was an increased sensitivity to activation of CANP by calcium (Ca). In addition, there was an enhancement of maximal activity of the enzyme. The effect was induced by secondary modification of the diabetic state, but not genetical factors. Several lines of evidence suggest that the CANP is responsible for 92 K dalton protein in diabetic skeletal muscles. Among the evidence are the following: a) The 92 K band in the diabetic muscles was lower than in the prediabetic mouse and restored by the addition of 2 mM EDTA and 2 mM EGTA. b) The band was reduced by increasing the Ca content and neutral pH in the non-diabetic normal muscles. c) E-64-C, a CANP inhibitor, restored the 92 K component reduced by the diabetic state. Since the band in denervated muscles was not changed by the Ca chelating agents, the reduction of the band in the diabetic muscles is related with musculotrophic factors, not diabetic neuropathy. These results suggest that diabetic amyotrophy may be regarded as a phenomenon linked to an increase in intracellular Ca ions and an increase in CANP activity. PMID:2561275

  10. Assessment of bioelectrical activity of synergistic muscles during pelvic floor muscles activation in postmenopausal women with and without stress urinary incontinence: a preliminary observational study

    PubMed Central

    Ptaszkowski, Kuba; Paprocka-Borowicz, Małgorzata; Słupska, Lucyna; Bartnicki, Janusz; Dymarek, Robert; Rosińczuk, Joanna; Heimrath, Jerzy; Dembowski, Janusz; Zdrojowy, Romuald

    2015-01-01

    Objective Muscles such as adductor magnus (AM), gluteus maximus (GM), rectus abdominis (RA), and abdominal external and internal oblique muscles are considered to play an important role in the treatment of stress urinary incontinence (SUI), and the relationship between contraction of these muscles and pelvic floor muscles (PFM) has been established in previous studies. Synergistic muscle activation intensifies a woman’s ability to contract the PFM. In some cases, even for continent women, it is not possible to fully contract their PFM without involving the synergistic muscles. The primary aim of this study was to assess the surface electromyographic activity of synergistic muscles to PFM (SPFM) during resting and functional PFM activation in postmenopausal women with and without SUI. Materials and methods This study was a preliminary, prospective, cross-sectional observational study and included volunteers and patients who visited the Department and Clinic of Urology, University Hospital in Wroclaw, Poland. Forty-two patients participated in the study and were screened for eligibility criteria. Thirty participants satisfied the criteria and were categorized into two groups: women with SUI (n=16) and continent women (n=14). The bioelectrical activity of PFM and SPFM (AM, RA, GM) was recorded with a surface electromyographic instrument in a standing position during resting and functional PFM activity. Results Bioelectrical activity of RA was significantly higher in the incontinent group than in the continent group. These results concern the RA activity during resting and functional PFM activity. The results for other muscles showed no significant difference in bioelectrical activity between groups. Conclusion In women with SUI, during the isolated activation of PFM, an increased synergistic activity of RA muscle was observed; however, this activity was not observed in asymptomatic women. This may indicate the important accessory contribution of these muscles in the

  11. Comparison of muscle force, muscle endurance, and electromyogram activity during an expedition at high altitude

    NASA Astrophysics Data System (ADS)

    Terasawa, K.; Fujiwara, T.; Sakai, A.; Yanagidaira, N.; Asano, K.; Yanagisawa, K.; Kashimura, N.; Ueda, G.; Wu, T.; Zhang, Y.

    1996-09-01

    Handgrip force (HF), maximal pinch force (MF), muscle endurance (ME), and the median power frequency (MdPF) of the activity shown in the electromyogram (EMG) were studied at various altitudes in eight normal healthy subjects. MF and ME were measured between the index finger and thumb, and all measurements were obtained at altitudes ranging from 610 to 4860 m during an expedition in the Qinghai Plateau in China. With the change in altitude HF, ME, and MF showed no significant change. Compared to the MdPF at 2260 m on ascent, the MdPF at other altitudes showed a significant decrease ( P<0.01). Thus, we conclude that muscle performance (HF, MF, and ME) was not affected by the environment at high altitude. However, MdPF was affected and the mean MdPF at 610 m after the expedition did not recover to initial values of MdPF. We suggest these results may have been affected by fatigue and chronic exposure to the hypobaric hypoxic environment, since the members of the expedition party expressed feelings of sluggishness and fatigue after the expedition.

  12. Suboptimal Muscle Synergy Activation Patterns Generalize their Motor Function across Postures

    PubMed Central

    Sohn, M. Hongchul; Ting, Lena H.

    2016-01-01

    We used a musculoskeletal model to investigate the possible biomechanical and neural bases of using consistent muscle synergy patterns to produce functional motor outputs across different biomechanical conditions, which we define as generalizability. Experimental studies in cats demonstrate that the same muscle synergies are used during reactive postural responses at widely varying configurations, producing similarly-oriented endpoint force vectors with respect to the limb axis. However, whether generalizability across postures arises due to similar biomechanical properties or to neural selection of a particular muscle activation pattern has not been explicitly tested. Here, we used a detailed cat hindlimb model to explore the set of feasible muscle activation patterns that produce experimental synergy force vectors at a target posture, and tested their generalizability by applying them to different test postures. We used three methods to select candidate muscle activation patterns: (1) randomly-selected feasible muscle activation patterns, (2) optimal muscle activation patterns minimizing muscle effort at a given posture, and (3) generalizable muscle activation patterns that explicitly minimized deviations from experimentally-identified synergy force vectors across all postures. Generalizability was measured by the deviation between the simulated force direction of the candidate muscle activation pattern and the experimental synergy force vectors at the test postures. Force angle deviations were the greatest for the randomly selected feasible muscle activation patterns (e.g., >100°), intermediate for effort-wise optimal muscle activation patterns (e.g., ~20°), and smallest for generalizable muscle activation patterns (e.g., <5°). Generalizable muscle activation patterns were suboptimal in terms of effort, often exceeding 50% of the maximum possible effort (cf. ~5% in minimum-effort muscle activation patterns). The feasible muscle activation ranges of individual

  13. Hyaluronan mediates airway hyperresponsiveness in oxidative lung injury.

    PubMed

    Lazrak, Ahmed; Creighton, Judy; Yu, Zhihong; Komarova, Svetlana; Doran, Stephen F; Aggarwal, Saurabh; Emala, Charles W; Stober, Vandy P; Trempus, Carol S; Garantziotis, Stavros; Matalon, Sadis

    2015-05-01

    Chlorine (Cl2) inhalation induces severe oxidative lung injury and airway hyperresponsiveness (AHR) that lead to asthmalike symptoms. When inhaled, Cl2 reacts with epithelial lining fluid, forming by-products that damage hyaluronan, a constituent of the extracellular matrix, causing the release of low-molecular-weight fragments (L-HA, <300 kDa), which initiate a series of proinflammatory events. Cl2 (400 ppm, 30 min) exposure to mice caused an increase of L-HA and its binding partner, inter-α-trypsin-inhibitor (IαI), in the bronchoalveolar lavage fluid. Airway resistance following methacholine challenge was increased 24 h post-Cl2 exposure. Intratracheal administration of high-molecular-weight hyaluronan (H-HA) or an antibody against IαI post-Cl2 exposure decreased AHR. Exposure of human airway smooth muscle (HASM) cells to Cl2 (100 ppm, 10 min) or incubation with Cl2-exposed H-HA (which fragments it to L-HA) increased membrane potential depolarization, intracellular Ca(2+), and RhoA activation. Inhibition of RhoA, chelation of intracellular Ca(2+), blockade of cation channels, as well as postexposure addition of H-HA, reversed membrane depolarization in HASM cells. We propose a paradigm in which oxidative lung injury generates reactive species and L-HA that activates RhoA and Ca(2+) channels of airway smooth muscle cells, increasing their contractility and thus causing AHR. PMID:25747964

  14. Hyaluronan mediates airway hyperresponsiveness in oxidative lung injury

    PubMed Central

    Lazrak, Ahmed; Creighton, Judy; Yu, Zhihong; Komarova, Svetlana; Doran, Stephen F.; Aggarwal, Saurabh; Emala, Charles W.; Stober, Vandy P.; Trempus, Carol S.; Garantziotis, Stavros

    2015-01-01

    Chlorine (Cl2) inhalation induces severe oxidative lung injury and airway hyperresponsiveness (AHR) that lead to asthmalike symptoms. When inhaled, Cl2 reacts with epithelial lining fluid, forming by-products that damage hyaluronan, a constituent of the extracellular matrix, causing the release of low-molecular-weight fragments (L-HA, <300 kDa), which initiate a series of proinflammatory events. Cl2 (400 ppm, 30 min) exposure to mice caused an increase of L-HA and its binding partner, inter-α-trypsin-inhibitor (IαI), in the bronchoalveolar lavage fluid. Airway resistance following methacholine challenge was increased 24 h post-Cl2 exposure. Intratracheal administration of high-molecular-weight hyaluronan (H-HA) or an antibody against IαI post-Cl2 exposure decreased AHR. Exposure of human airway smooth muscle (HASM) cells to Cl2 (100 ppm, 10 min) or incubation with Cl2-exposed H-HA (which fragments it to L-HA) increased membrane potential depolarization, intracellular Ca2+, and RhoA activation. Inhibition of RhoA, chelation of intracellular Ca2+, blockade of cation channels, as well as postexposure addition of H-HA, reversed membrane depolarization in HASM cells. We propose a paradigm in which oxidative lung injury generates reactive species and L-HA that activates RhoA and Ca2+ channels of airway smooth muscle cells, increasing their contractility and thus causing AHR. PMID:25747964

  15. Defining feasible bounds on muscle activation in a redundant biomechanical task; practical implications of redundancy

    PubMed Central

    Sohn, M. Hongchul; McKay, J. Lucas; Ting, Lena H.

    2013-01-01

    Measured muscle activation patterns often vary significantly from musculoskeletal model predictions that use optimization to resolve redundancy. Although experimental muscle activity exhibits both inter- and intra-subject variability we lack adequate tools to quantify the biomechanical latitude that the nervous system has when selecting muscle activation patterns. Here, we identified feasible ranges of individual muscle activity during force production in a musculoskeletal model to quantify the degree to which biomechanical redundancy allows for variability in muscle activation patterns. In a detailed cat hindlimb model matched to the posture of three cats, we identified the lower and upper bounds on muscle activity in each of 31 muscles during static endpoint force production across different force directions and magnitudes. Feasible ranges of muscle activation were relatively unconstrained across force magnitudes such that only a few (0∼13%) muscles were found to be truly “necessary” (e.g. exhibited non-zero lower bounds) at physiological force ranges. Most muscles were “optional” having zero lower bounds, and frequently had “maximal” upper bounds as well. Moreover, “optional” muscles were never selected by optimization methods that either minimized muscle stress, or that scaled the pattern required for maximum force generation. Therefore, biomechanical constraints were generally insufficient to restrict or specify muscle activation levels for producing a force in a given direction, and many muscle patterns exist that could deviate substantially from one another but still achieve the task. Our approach could be extended to identify the feasible limits of variability in muscle activation patterns in dynamic tasks such as walking. PMID:23489436

  16. Unilateral hip osteoarthritis: Its effects on preoperative lower limb muscle activation and intramuscular coordination patterns.

    PubMed

    Schmidt, André; Stief, Felix; Lenarz, Katharina; Froemel, Dara; Lutz, Frederick; Barker, John; Meurer, Andrea

    2016-03-01

    The objective of this study was to test if patients with unilateral hip osteoarthritis (OA) show greater muscle activity asymmetry between their affected and non-affected limbs than healthy controls between their left and right limbs. Seventeen patients with unilateral hip OA (7 females, 10 males) and 17 age-matched healthy controls (7 females, 10 males) participated in this study. Both groups performed instrumented gait analysis at comparable speeds. Muscle activity was recorded simultaneously for the tibialis anterior (TA), gastrocnemius medialis (GM), vastus lateralis (VL), semitendinosus (ST), tensor fasciae latae (TFL), and gluteus medius (GLM) muscles. In hip OA patients, EMG data showed greater activity of the TA muscle in the non-affected limb, and greater TFL muscle activity in the affected limb. Compared to healthy controls, greater asymmetries between paired limbs were observed for the TA and GM muscles. Finally, the TFL muscle of the affected limb contributed more to the total limb muscle activity than did the non-affected limb. The observed alterations in TA and GM muscle activity in hip OA patients may be due to the greater peak braking and peak vertical forces measured in the non-affected limb. Contrary to this, greater TLF muscle activity of the affected limb indicates the demands put on stabilizing the hip during stance phase. Further studies are necessary to test whether leg length discrepancy affects muscle activation alterations between the affected and non-affected limb in unilateral hip OA patients. PMID:26979904

  17. Synthetic muscle promoters: activities exceeding naturally occurring regulatory sequences

    NASA Technical Reports Server (NTRS)

    Li, X.; Eastman, E. M.; Schwartz, R. J.; Draghia-Akli, R.

    1999-01-01

    Relatively low levels of expression from naturally occurring promoters have limited the use of muscle as a gene therapy target. Myogenic restricted gene promoters display complex organization usually involving combinations of several myogenic regulatory elements. By random assembly of E-box, MEF-2, TEF-1, and SRE sites into synthetic promoter recombinant libraries, and screening of hundreds of individual clones for transcriptional activity in vitro and in vivo, several artificial promoters were isolated whose transcriptional potencies greatly exceed those of natural myogenic and viral gene promoters.

  18. Suppression of the increasing level of acetylcholine-stimulated intracellular Ca2+ in guinea pig airway smooth muscle cells by mabuterol

    PubMed Central

    SONG, XIRUI; ZHAO, CHAO; DAI, CAILING; REN, YANXIN; AN, NAN; WEN, HUIMIN; PAN, LI; CHENG, MAOSHENG; ZHANG, YUYANG

    2015-01-01

    The present study aimed to establish an effective method for the in vitro culture of guinea pig airway smooth muscle (ASM) cells, and also investigate the suppressive effect of mabuterol hydrochloride (Mab) on the increased level of intracellular Ca2+ in ASM cells induced with acetylcholine (Ach). Two different methods, i.e. with or without collagenase to pretreat tracheal tissues, were applied to the manufacture of ASM cells. Cell viability was determined with the 3-(4,5-dimethylthinazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Immunocytochemistry and immunofluorescence were used for the identification of ASM cells. Different concentration levels (10−3, 10−4, 10−5, 10−6 and 10−7 mmol/l) of Mab were administered 5 min before Ach (10−4 M) treatment, respectively. The Ca2+ fluorescent probe, Fura-2/AM or Fluo-3/AM were applied to the inspection of Ca2+ fluorescent intensity with Varioskan Flash, immunocytometry systems and an inverted system microscope, respectively. The results showed that the fresh method, in which isolated tracheal tissues were previously treated with collagenase for 20 min, was more advantageous for the preparation of guinea pig ASM cells compared to when the enzyme was not used. The time for the ASM cells to initially migrate out of the ‘tissue blocks’ and the culture having to be generated due to the thick cell density was significantly less. On identification with immunocytochemistry or immunofluorescent staining, >95% of the cells were ASM cells. Mab (10−3−10−7 mmol/l) significantly suppressed the elevation of intracellular Ca2+ induced by Ach in a concentration-dependent manner. The inhibitory rates of intracellular Ca2+ by different concentrations of Mab, from low to high, were 14.93, 24.73, 40.06, 48.54 and 57.13%, respectively, when Varioskan Flash was used for determination. In conclusion, this novel method has a shorter harvesting period for ASM cells. Mab can suppress the increasing level of intracellular Ca2

  19. Exercise and airway injury in athletes.

    PubMed

    Couto, Mariana; Silva, Diana; Delgado, Luis; Moreira, André

    2013-01-01

    Olympic level athletes present an increased risk for asthma and allergy, especially those who take part in endurance sports, such as swimming or running, and in winter sports. Classical postulated mechanisms behind EIA include the osmotic, or airway-drying, hypothesis. Hyperventilation leads to evaporation of water and the airway surface liquid becomes hyperosmolar, providing a stimulus for water to move from any cell nearby, which results in the shrinkage of cells and the consequent release of inflammatory mediators that cause airway smooth muscle contraction. But the exercise-induced asthma/bronchoconstriction explanatory model in athletes probably comprises the interaction between environmental training factors, including allergens and ambient conditions such as temperature, humidity and air quality; and athlete's personal risk factors, such as genetic and neuroimmuneendocrine determinants. After the stress of training and competitions athletes experience higher rate of upper respiratory tract infections (URTI), compared with lesser active individuals. Increasing physical activity in non-athletes is associated with a decreased risk of URTI. Heavy exercise induces marked immunodepression which is multifactorial in origin. Prolonged, high intensity exercise temporarily impairs the immune competence while moderate activity may enhance immune function. The relationship between URTI and exercise is affected by poorly known individual determinants such genetic susceptibility, neurogenic mediated immune inflammation and epithelial barrier dysfunction. Further studies should better define the aetiologic factors and mechanisms involved in the development of asthma in athletes, and propose relevant preventive and therapeutic measures. PMID:23697359

  20. The activities of lipases and carnitine palmitoyl-transferase in muscles from vertebrates and invertebrates

    PubMed Central

    Crabtree, B.; Newsholme, E. A.

    1972-01-01

    1. The activities of tri-, di- and mono-glyceride lipase and carnitine palmitoyltransferase were measured in homogenates of a variety of muscles. These activities were used to estimate the rate of utilization of glycerides and fatty acids by muscle. In muscles whose estimated rates of fat utilization can be compared with rates calculated for the intact muscle from such information as O2 uptake, there is reasonable agreement between the estimated and calculated rates. 2. In all