scholarly journals Airway smooth muscle relaxation is impaired in mice lacking the p47phoxsubunit of NAD(P)H oxidase

2008 ◽  
Vol 294 (1) ◽  
pp. L139-L148 ◽  
Author(s):  
Pasquale Chitano ◽  
Lu Wang ◽  
Stanley N. Mason ◽  
Richard L. Auten ◽  
Erin N. Potts ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Muscle Relaxation ◽  
Reactive Oxygen ◽  
Smooth Muscle Relaxation ◽  
Oxygen Species ◽  
Wild Type ◽  
Shortening Velocity

NAD(P)H oxidase is one of the critical enzymes mediating cellular production of reactive oxygen species and has a central role in airway smooth muscle (ASM) cell proliferation. Since reactive oxygen species also affect ASM contractile response, we hypothesized a regulatory role of NAD(P)H oxidase in ASM contractility. We therefore studied ASM function in wild-type mice (C57BL/6J) and mice deficient in a component (p47phox) of NAD(P)H oxidase. In histological sections of the trachea, we found that the area occupied by ASM was 17% more in p47phox−/−than in wild-type mice. After correcting for the difference in ASM content, we found that force generation did not vary between the two genotypes. Similarly, their ASM shortening velocity, maximal power, and sensitivity to acetylcholine, as well as airway responsiveness to methacholine in vivo, were not significantly different. The main finding of this study was a significantly reduced ASM relaxation in p47phox−/−compared with wild-type mice both during the stimulus and after the end of stimulation. The tension relaxation attained at the 20th second of electric field stimulation was, respectively, 17.6 ± 2.4 and 9.2 ± 2.3% in null and wild-type mice ( P <0.01 by t-test). Similar significant differences were found in the rate of tension relaxation and the time required to reduce tension by one-half. Our data suggest that NAD(P)H oxidase may have a role in the structural arrangement and mechanical properties of the airway tissue. Most importantly, we report the first evidence that the p47phoxsubunit of NAD(P)H oxidase plays a role in ASM relaxation.

Exposure of differentiated airway smooth muscle cells to serum stimulates both induction of hypoxia-inducible factor-1α and airway responsiveness to ACh

2007 ◽  
Vol 293 (4) ◽  
pp. L913-L922 ◽  
Author(s):  
Georgia Chachami ◽  
Apostolia Hatziefthimiou ◽  
Panagiotis Liakos ◽  
Maria G. Ioannou ◽  
Georgios K. Koukoulis ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Hypoxia Inducible Factor ◽  
Reactive Oxygen ◽  
Serum Starvation ◽  
Airway Smooth Muscle Cells ◽  
Oxygen Species ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatidylinositol 3

Airway smooth muscle (ASM) cells are characterized by phenotypic plasticity and can switch between differentiated and proliferative phenotypes. In rabbit tracheal ASM cells that had been differentiated in vitro by serum starvation, readdition of FBS caused initiation of proliferation and induction of nuclear and transcriptionally active hypoxia-inducible factor (HIF)-1α. In addition, FBS stimulated the induction of HIF-1α by the hypoxia mimetic cobalt. Treatment with actinomycin D, cycloheximide, the phosphatidylinositol 3-kinase inhibitors LY-294002 and wortmannin or the reactive oxygen species scavenger diphenyleneiodonium inhibited the FBS-dependent induction of HIF-1α. These data indicate that, in differentiated ASM cells, FBS upregulates HIF-1α by a transcription-, translation-, phosphatidylinositol 3-kinase-, and reactive oxygen species-dependent mechanism. Interestingly, addition of FBS and cobalt also induced HIF-1α in organ cultures of rabbit trachea strips and synergistically increased their contractile response to ACh, suggesting that HIF-1α might be implicated in airway hypercontractility.

Catecholamines augment collateral vessel growth and angiogenesis in hindlimb ischemia

2005 ◽  
Vol 289 (2) ◽  
pp. H947-H959 ◽  
Author(s):  
Dan Chalothorn ◽  
Hua Zhang ◽  
Jason A. Clayton ◽  
Steven A. Thomas ◽  
James E. Faber
Keyword(s):  
Reactive Oxygen Species ◽  
Smooth Muscle ◽  
Smooth Muscle Actin ◽  
Reactive Oxygen ◽  
Lumen Diameter ◽  
Oxygen Species ◽  
Wild Type ◽  
Tissue Ischemia ◽  
Leukocyte Accumulation ◽  
Collateral Growth

Catecholamine stimulation of α1-adrenoceptors exerts growth factor-like activity, mediated by generation of reactive oxygen species, on arterial smooth muscle cells and adventitial fibroblasts and contributes to hypertrophy and hyperplasia in models of vascular injury and disease. Adrenergic trophic activity also contributes to flow-mediated positive arterial remodeling by augmenting proliferation and leukocyte accumulation. To further examine this concept, we studied whether catecholamines contribute to collateral growth and angiogenesis in hindlimb insufficiency. Support for this hypothesis includes the above-mentioned studies, evidence that ischemia augments norepinephrine release from sympathetic nerves, and proposed involvement of reactive oxygen species in angiogenesis and collateral growth. Mice deficient in catecholamine synthesis [by gene deletion of dopamine β-hydroxylase (DBH−/−)] were studied. At 3 wk after femoral artery ligation, increases in adductor muscle perfusion were similar in DBH−/− and wild-type mice, whereas recovery of plantar perfusion and calf microsphere flow were attenuated, although not significantly. Preexisting collaterals in adductor of wild-type mice showed increases in lumen diameter (60%) and medial and adventitial thickness (57 and 119%, P < 0.05 here and below). Lumen diameter increased similarly in DBH−/− mice (52%); however, increases in medial and adventitial thicknesses were reduced (30 and 65%). Leukocyte accumulation in the adventitia/periadventitia of collaterals was 39% less in DBH−/− mice. Increased density of α-smooth muscle actin-positive vessels in wild-type adductor (45%) was inhibited in DBH−/− mice (2%). Although both groups experienced similar atrophy in the gastrocnemius (∼22%), the increase in capillary-to-muscle fiber ratio in wild-type mice (21%) was inhibited in DBH−/− mice (7%). These data suggest that catecholamines may contribute to collateral growth and angiogenesis in tissue ischemia.

scholarly journals Pathophysiological regulation of lung function by the free fatty acid receptor FFA4

2020 ◽  
Author(s):  
Rudi Prihandoko ◽  
Davinder Kaur ◽  
Coen H. Wiegman ◽  
Elisa Alvarez-Curto ◽  
Chantal Donovan ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Muscle Relaxation ◽  
Smooth Muscle Relaxation ◽  
Chronic Obstructive ◽  
Omega 3 ◽  
Airway Diseases ◽  
Number Of Patients

AbstractIncreased prevalence of inflammatory airway diseases including asthma and chronic obstructive pulmonary disease (COPD) together with a significant number of patients being inadequately controlled by current frontline treatments means that there is a need to define novel therapeutic targets for these conditions1. Here we investigate a member of the G protein-coupled receptor (GPCR) family, FFA4, which responds to free circulating fatty acids, including dietary omega-3 fatty acids found in fish oils2–4. Although usually associated with metabolic responses linked with food intake, we show that FFA4 is expressed in the lung where it is coupled to Gq/11-signalling. Activation of FFA4 by drug-like agonists produced relaxation of murine airway smooth muscle mediated, at least in part, by the release of the prostaglandin PGE2 that subsequently acts on EP2 prostanoid receptors. In normal mice, activation of FFA4 resulted in a decrease in lung resistance. Importantly, in acute and chronic ozone models of pollution-mediated inflammation, and in house-dust mite and cigarette smoke-induced inflammatory disease, FFA4 agonists acted to reduce airway resistance, whilst this response was absent in mice lacking expression of FFA4. The expression profile of FFA4 in human lung was very similar to that observed in mice and the response to FFA4/FFA1 agonists similarly mediated human airway smooth muscle relaxation. Hence, our study provides evidence that pharmacological targeting of lung FFA4, and possibly combined activation of FFA4 and FFA1, has in vivo efficacy that might have therapeutic value in the treatment of bronchoconstriction associated with inflammatory airway diseases such as asthma and COPD.

MYB134-RNAi poplar plants show reduced tannin synthesis in leaves but not roots, and increased susceptibility to oxidative stress

2020 ◽  
Vol 71 (20) ◽  
pp. 6601-6611
Author(s):  
Geraldine Gourlay ◽  
Dawei Ma ◽  
Axel Schmidt ◽  
C Peter Constabel
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Condensed Tannin ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Rna Seq ◽  
Wild Type ◽  
And Control ◽  
Increased Susceptibility

Abstract The importance of the poplar MYB134 gene in controlling condensed tannin (CT) biosynthesis was tested by suppressing its expression using RNA interference (RNAi). MYB134-RNAi plants grew normally but showed reduced accumulation of stress-induced CTs in leaves. RNA-seq analysis indicated that flavonoid- and CT-related genes, as well as additional CT regulators, were strongly and specifically down-regulated by MYB134 suppression. This confirmed that the primary MYB134 target is the leaf flavonoid and CT pathway. Root CT accumulation was not impacted by MYB suppression, suggesting that additional CT regulators are active in roots and emphasizing the complexity of the regulation of CTs in poplar. To test the effect of CT down-regulation on oxidative stress resistance, leaves of MYB134-RNAi and control plants were exposed to the reactive oxygen species generator methyl viologen. MYB134-RNAi leaves sustained significantly more photosystem II damage, as seen in reduced chlorophyll fluorescence, compared with wild-type leaves. MYB134-RNAi leaves also contained more hydrogen peroxide, a reactive oxygen species, compared with the wild type. Our data thus corroborate the hypothesis that CT can act as an antioxidant in vivo and protect against oxidative stress. Overall, MYB134 was shown to be a central player in the regulation of CT synthesis in leaves.

scholarly journals Cdc42GAP, reactive oxygen species, and the vimentin network

2009 ◽  
Vol 297 (2) ◽  
pp. C299-C309 ◽  
Author(s):  
Qing-Fen Li ◽  
Amy M. Spinelli ◽  
Dale D. Tang
Keyword(s):  
Reactive Oxygen Species ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Reactive Oxygen ◽  
Muscle Cells ◽  
Oxygen Species ◽  
Wild Type ◽  
Vitro Assay ◽  
Contractile Activation

Cdc42GAP (GTPase-activating protein) has been implicated in the regulation of cell motility, adhesion, proliferation, and apoptosis. In this study, Cdc42GAP was cloned from smooth muscle tissues. Cdc42GAP, but not inactive R282A Cdc42GAP (alanine substitution at arginine-282), enhanced the GTP hydrolysis of Cdc42 in an in vitro assay. Furthermore, we developed an assay to evaluate the activity of Cdc42GAP in vivo. Stimulation of smooth muscle cells with 5-hydroxytryptamine (5-HT) resulted in the decrease in Cdc42GAP activity. The agonist-induced GAP suppression was reversed by reactive oxygen species inhibitors. Treatment with hydrogen peroxide also inhibited GAP activity in smooth muscle cells. Because the vimentin cytoskeleton undergoes dynamic changes in response to contractile activation, we evaluated the role of Cdc42GAP in regulating vimentin filaments. Smooth muscle cells were infected with retroviruses encoding wild-type Cdc42GAP or its R282A mutant. Expression of wild-type Cdc42GAP, but not mutant R282A GAP, inhibited the increase in the activation of Cdc42 upon agonist stimulation. Phosphorylation of p21-activated kinase (PAK) at Thr-423 (an indication of PAK activation), vimentin phosphorylation (Ser-56), partial disassembly and spatial remodeling, and contraction were also attenuated in smooth muscle cells expressing Cdc42GAP. Our results suggest that the activity of Cdc42GAP is regulated upon contractile activation, which is mediated by intracellular ROS. Cdc42GAP regulates the vimentin network through the Cdc42-PAK pathway in smooth muscle cells during 5-HT stimulation.

scholarly journals Arterial Smooth Muscle Mitochondria Amplify Hydrogen Peroxide Microdomains Functionally Coupled to L-Type Calcium Channels

2015 ◽  
Vol 117 (12) ◽  
pp. 1013-1023 ◽  
Author(s):  
Nathan L. Chaplin ◽  
Madeline Nieves-Cintrón ◽  
Adriana M. Fresquez ◽  
Manuel F. Navedo ◽  
Gregory C. Amberg
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Smooth Muscle ◽  
Calcium Channels ◽  
Intracellular Signaling ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Arterial Smooth Muscle ◽  
The Impact

Rationale: Mitochondria are key integrators of convergent intracellular signaling pathways. Two important second messengers modulated by mitochondria are calcium and reactive oxygen species. To date, coherent mechanisms describing mitochondrial integration of calcium and oxidative signaling in arterial smooth muscle are incomplete. Objective: To address and add clarity to this issue, we tested the hypothesis that mitochondria regulate subplasmalemmal calcium and hydrogen peroxide microdomain signaling in cerebral arterial smooth muscle. Methods and Results: Using an image-based approach, we investigated the impact of mitochondrial regulation of L-type calcium channels on subcellular calcium and reactive oxygen species signaling microdomains in isolated arterial smooth muscle cells. Our single-cell observations were then related experimentally to intact arterial segments and to living animals. We found that subplasmalemmal mitochondrial amplification of hydrogen peroxide microdomain signaling stimulates L-type calcium channels, and that this mechanism strongly impacts the functional capacity of the vasoconstrictor angiotensin II. Importantly, we also found that disrupting this mitochondrial amplification mechanism in vivo normalized arterial function and attenuated the hypertensive response to systemic endothelial dysfunction. Conclusions: From these observations, we conclude that mitochondrial amplification of subplasmalemmal calcium and hydrogen peroxide microdomain signaling is a fundamental mechanism regulating arterial smooth muscle function. As the principle components involved are fairly ubiquitous and positioning of mitochondria near the plasma membrane is not restricted to arterial smooth muscle, this mechanism could occur in many cell types and contribute to pathological elevations of intracellular calcium and increased oxidative stress associated with many diseases.

scholarly journals Requirement for Reactive Oxygen Species in Serum-induced and Platelet-derived Growth Factor-induced Growth of Airway Smooth Muscle

1999 ◽  
Vol 274 (28) ◽  
pp. 20017-20026 ◽  
Author(s):  
Sukhdev S. Brar ◽  
Thomas P. Kennedy ◽  
A. Richard Whorton ◽  
Thomas M. Murphy ◽  
Pasquale Chitano ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Smooth Muscle ◽  
Growth Factor ◽  
Airway Smooth Muscle ◽  
Reactive Oxygen ◽  
Platelet Derived Growth Factor ◽  
Oxygen Species

scholarly journals Production and scavenging of reactive oxygen species both affect reproductive success in male and female Drosophila melanogaster

2021 ◽  
Author(s):  
Biz R. Turnell ◽  
Luisa Kumpitsch ◽  
Klaus Reinhardt
Keyword(s):  
Reactive Oxygen Species ◽  
Drosophila Melanogaster ◽  
Reactive Oxygen ◽  
Cellular Aging ◽  
Ros Production ◽  
Oxygen Species ◽  
Wild Type ◽  
Ros Scavenging ◽  
Respiratory Pathway ◽  
Male And Female

AbstractSperm aging is accelerated by the buildup of reactive oxygen species (ROS), which cause oxidative damage to various cellular components. Aging can be slowed by limiting the production of mitochondrial ROS and by increasing the production of antioxidants, both of which can be generated in the sperm cell itself or in the surrounding somatic tissues of the male and female reproductive tracts. However, few studies have compared the separate contributions of ROS production and ROS scavenging to sperm aging, or to cellular aging in general. We measured reproductive fitness in two lines of Drosophila melanogaster genetically engineered to (1) produce fewer ROS via expression of alternative oxidase (AOX), an alternative respiratory pathway; or (2) scavenge fewer ROS due to a loss-of-function mutation in the antioxidant gene dj-1β. Wild-type females mated to AOX males had increased fecundity and longer fertility durations, consistent with slower aging in AOX sperm. Contrary to expectations, fitness was not reduced in wild-type females mated to dj-1β males. Fecundity and fertility duration were increased in AOX and decreased in dj-1β females, indicating that female ROS levels may affect aging rates in stored sperm and/or eggs. Finally, we found evidence that accelerated aging in dj-1β sperm may have selected for more frequent mating. Our results help to clarify the relative roles of ROS production and ROS scavenging in the male and female reproductive systems.

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