scholarly journals The Contraction of Smooth Muscle Cells of Intrapulmonary Arterioles Is Determined by the Frequency of Ca2+ Oscillations Induced by 5-HT and KCl

2005 ◽  
Vol 125 (6) ◽  
pp. 555-567 ◽  
Author(s):  
Jose F. Perez ◽  
Michael J. Sanderson
Keyword(s):  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Confocal Microscopy ◽  
Smooth Muscle Cells ◽  
Phase Contrast ◽  
Muscle Cells ◽  
Low Frequencies ◽  
Scanning Confocal Microscopy ◽  
Agonist Concentration ◽  
Mouse Lungs

Increased resistance of the small blood vessels within the lungs is associated with pulmonary hypertension and results from a decrease in size induced by the contraction of their smooth muscle cells (SMCs). To study the mechanisms that regulate the contraction of intrapulmonary arteriole SMCs, the contractile and Ca2+ responses of the arteriole SMCs to 5-hydroxytrypamine (5-HT) and KCl were observed with phase-contrast and scanning confocal microscopy in thin lung slices cut from mouse lungs stiffened with agarose and gelatin. 5-HT induced a concentration-dependent contraction of the arterioles. Increasing concentrations of extracellular KCl induced transient contractions in the SMCs and a reduction in the arteriole luminal size. 5-HT induced oscillations in [Ca2+]i within the SMCs, and the frequency of these Ca2+ oscillations was dependent on the agonist concentration and correlated with the extent of sustained arteriole contraction. By contrast, KCl induced Ca2+ oscillations that occurred with low frequencies and were preceded by small, localized transient Ca2+ events. The 5-HT–induced Ca2+ oscillations and contractions occurred in the absence of extracellular Ca2+ and were resistant to Ni2+ and nifedipine but were abolished by caffeine. KCl-induced Ca2+ oscillations and contractions were abolished by the absence of extracellular Ca2+ and the presence of Ni2+, nifedipine, and caffeine. Arteriole contraction was induced or abolished by a 5-HT2–specific agonist or antagonist, respectively. These results indicate that 5-HT, acting via 5-HT2 receptors, induces arteriole contraction by initiating Ca2+ oscillations and that KCl induces contraction via Ca2+ transients resulting from the overfilling of internal Ca2+ stores. We hypothesize that the magnitude of the sustained intrapulmonary SMC contraction is determined by the frequency of Ca2+ oscillations and also by the relaxation rate of the SMC.

Endothelin-induced contraction of bronchiole and pulmonary arteriole smooth muscle cells is regulated by intracellular Ca2+ oscillations and Ca2+ sensitization

2007 ◽  
Vol 293 (4) ◽  
pp. L1000-L1011 ◽  
Author(s):  
Jose F. Perez-Zoghbi ◽  
Michael J. Sanderson
Keyword(s):  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Confocal Microscopy ◽  
Smooth Muscle Cells ◽  
Elevated Level ◽  
Phase Contrast ◽  
Muscle Cells ◽  
Mouse Lung ◽  
Pulmonary Arteriole ◽  
Intracellular Ca

Endothelin-1 (ET) induces increases in intracellular Ca2+ concentration ([Ca2+]i), Ca2+ sensitization, and contraction of both bronchiole and pulmonary arteriole smooth muscle cells (SMCs) and may play an important role in the pathophysiology of asthma and pulmonary hypertension. However, because it remains unclear how changes in [Ca2+]i and the Ca2+ sensitivity regulate SMC contraction, we have studied mouse lung slices with phase-contrast and confocal microscopy to correlate the ET-induced contraction with the changes in [Ca2+]i and Ca2+ sensitivity of bronchiole and arteriole SMCs. In comparison with acetylcholine (ACh) or serotonin (5-HT), ET induced a stronger and long-lasting contraction of both bronchioles and arterioles. This ET-induced contraction was associated with prominent asynchronous Ca2+ oscillations that were propagated as Ca2+ waves along the SMCs. These Ca2+ oscillations were mediated by cyclic intracellular Ca2+ release and required external Ca2+ for their maintenance. Importantly, as the frequency of the Ca2+ oscillations increased, the extent of contraction increased. ET-induced contraction was also associated with an increase in Ca2+ sensitivity. In “model” slices in which the [Ca2+]i was constantly maintained at an elevated level by pretreatment of slices with caffeine and ryanodine, the addition of ET increased bronchiole and arteriole contraction. These results indicate that ET-induced contraction of bronchiole and arteriole SMCs is regulated by the frequency of Ca2+ oscillations and by increasing the sensitivity of the contractile machinery to Ca2+.

scholarly journals The Frequency of Calcium Oscillations Induced by 5-HT, ACH, and KCl Determine the Contraction of Smooth Muscle Cells of Intrapulmonary Bronchioles

2005 ◽  
Vol 125 (6) ◽  
pp. 535-553 ◽  
Author(s):  
Jose F. Perez ◽  
Michael J. Sanderson
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Phase Contrast ◽  
Low Frequency ◽  
Muscle Cells ◽  
Calcium Oscillations ◽  
Mouse Lung ◽  
Lung Slice ◽  
Agonist Concentration ◽  
High Concentrations

Increased resistance of airways or blood vessels within the lung is associated with asthma or pulmonary hypertension and results from contraction of smooth muscle cells (SMCs). To study the mechanisms regulating these contractions, we developed a mouse lung slice preparation containing bronchioles and arterioles and used phase-contrast and confocal microscopy to correlate the contractile responses with changes in [Ca2+]i of the SMCs. The airways are the focus of this study. The agonists, 5-hydroxytrypamine (5-HT) and acetylcholine (ACH) induced a concentration-dependent contraction of the airways. High concentrations of KCl induced twitching of the airway SMCs but had little effect on airway size. 5-HT and ACH induced asynchronous oscillations in [Ca2+]i that propagated as Ca2+ waves within the airway SMCs. The frequency of the Ca2+ oscillations was dependent on the agonist concentration and correlated with the extent of sustained airway contraction. In the absence of extracellular Ca2+ or in the presence of Ni2+, the frequency of the Ca2+ oscillations declined and the airway relaxed. By contrast, KCl induced low frequency Ca2+ oscillations that were associated with SMC twitching. Each KCl-induced Ca2+ oscillation consisted of a large Ca2+ wave that was preceded by multiple localized Ca2+ transients. KCl-induced responses were resistant to neurotransmitter blockers but were abolished by Ni2+ or nifedipine and the absence of extracellular Ca2+. Caffeine abolished the contractile effects of 5-HT, ACH, and KCl. These results indicate that (a) 5-HT and ACH induce airway SMC contraction by initiating Ca2+ oscillations, (b) KCl induces Ca2+ transients and twitching by overloading and releasing Ca2+ from intracellular stores, (c) a sustained, Ni2+-sensitive, influx of Ca2+ mediates the refilling of stores to maintain Ca2+ oscillations and, in turn, SMC contraction, and (d) the magnitude of sustained airway SMC contraction is regulated by the frequency of Ca2+ oscillations.

Elevated levels of activin A in clinical and experimental pulmonary hypertension

2009 ◽  
Vol 106 (4) ◽  
pp. 1356-1364 ◽  
Author(s):  
Arne Yndestad ◽  
Karl-Otto Larsen ◽  
Erik Øie ◽  
Thor Ueland ◽  
Camilla Smith ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Transforming Growth Factor ◽  
Experimental Studies ◽  
Plasminogen Activator Inhibitor ◽  
Muscle Cells ◽  
Activin A ◽  
Plasminogen Activator Inhibitor 1 ◽  
And Control

Activin A, a member of the transforming growth factor (TGF)-β superfamily, is involved in regulation of tissue remodeling and inflammation. Herein, we wanted to explore a role for activin A in pulmonary hypertension (PH). Circulating levels of activin A and its binding protein follistatin were measured in patients with PH ( n = 47) and control subjects ( n = 14). To investigate synthesis and localization of pulmonary activin A, we utilized an experimental model of hypoxia-induced PH. In mouse lungs, we also explored signaling pathways that can be activated by activin A, such as phosphorylation of Smads, which are mediators of TGF-β signaling. Possible pathophysiological mechanisms initiated by activin A were explored by exposing pulmonary arterial smooth muscle cells in culture to this cytokine. Elevated levels of activin A and follistatin were found in patients with PH, and activin A levels were significantly related to mortality. Immunohistochemistry of lung autopsies from PH patients and lungs with experimental PH localized activin A primarily to alveolar macrophages and bronchial epithelial cells. Mice with PH exhibited increased pulmonary levels of mRNA for activin A and follistatin in the lungs, and also elevated pulmonary levels of phosphorylated Smad2. Finally, we found that activin A increased proliferation and induced gene expression of endothelin-1 and plasminogen activator inhibitor-1 in pulmonary artery smooth muscle cells, mediators that could contribute to vascular remodeling. Our findings in both clinical and experimental studies suggest a role for activin A in the development of various types of PH.

Enhance Smooth Muscle Cells Apoptosis Associated With Pulmonary Arterial Remodeling in Dogs Affected With Pulmonary Hypertension Secondary to Degenerative Mitral Valve Disease

2021 ◽  
Author(s):  
Siriwan Sakarin ◽  
Anudep Rungsipipat ◽  
Sirilak Disatian Surachetpong
Keyword(s):  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Mitral Valve ◽  
Pulmonary Artery ◽  
Smooth Muscle Cells ◽  
Mitral Valve Disease ◽  
Caspase 3 ◽  
Muscle Cells ◽  
Pulmonary Arterial ◽  
Medial Thickening

Abstract Background: Degenerative mitral valve disease (DMVD) is the most common cause of pulmonary hypertension (PH) in dogs. Medial thickening of the pulmonary artery is a major histopathological change in PH. A decrease in apoptosis of pulmonary arterial smooth muscle cells (SMCs) may be the cause of medial thickening. This study aimed to demonstrate the expression of apoptosis molecules in the pulmonary artery of dogs affected with PH secondary to DMVD (DMVD+PH) compared to DMVD without PH (DMVD) and healthy dogs (control). Lung samples were collected from three groups including control (n=5), DMVD (n=7) and DMVD+PH (n=7) groups. Masson trichrome and apoptotic proteins including Bax, Bcl2 and caspase-3 and -8, were stained. Results: The medial thickness in the DMVD and DMVD+PH groups was greater than in the control group and it was greatest in the DMVD+PH group. Bax, Bcl2 and caspase-3 and -8 were expressed mainly in the medial layer of the pulmonary artery. The percentages of Bax and caspase-3 and -8 positive cells were higher in the DMVD group compared to the DMVD+PH group, whereas the percentage of Bcl2-positive cells was increased in the DMVD and DMVD+PH groups. These findings suggested that apoptosis of pulmonary arterial SMCs occurred mainly in the DMVD group and decreased dramatically in the DMVD+PH group. Conclusions: An increase in the medial thickness in dogs affected with PH secondary to DMVD may occur due to a decrease in apoptosis of pulmonary arterial SMCs.

scholarly journals Untargeted Metabolic Profiling Cell-Based Approach of Pulmonary Artery Smooth Muscle Cells in Response to High Glucose and the Effect of the Antioxidant Vitamins D and E

Metabolites ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 87 ◽  
Author(s):  
Abdulwahab Alamri ◽  
Abdulhadi Burzangi ◽  
Paul Coats ◽  
David Watson
Keyword(s):  
Reactive Oxygen Species ◽  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Pulmonary Artery ◽  
Smooth Muscle Cells ◽  
High Glucose ◽  
Muscle Cells ◽  
Oxygen Species ◽  
Pulmonary Arterial ◽  
Pulmonary Artery Smooth Muscle

Pulmonary arterial hypertension (PAH) is a multi-factorial disease characterized by the hyperproliferation of pulmonary artery smooth muscle cells (PASMCs). Excessive reactive oxygen species (ROS) formation resulted in alterations of the structure and function of pulmonary arterial walls, leading to right ventricular failure and death. Diabetes mellitus has not yet been implicated in pulmonary hypertension. However, recently, variable studies have shown that diabetes is correlated with pulmonary hypertension pathobiology, which could participate in the modification of pulmonary artery muscles. The metabolomic changes in PASMCs were studied in response to 25 mM of D-glucose (high glucose, or HG) in order to establish a diabetic-like condition in an in vitro setting, and compared to five mM of D-glucose (normal glucose, or LG). The effect of co-culturing these cells with an ideal blood serum concentration of cholecalciferol-D3 and tocopherol was also examined. The current study aimed to examine the role of hyperglycemia in pulmonary arterial hypertension by the quantification and detection of the metabolomic alteration of smooth muscle cells in high-glucose conditions. Untargeted metabolomics was carried out using hydrophilic interaction liquid chromatography and high-resolution mass spectrometry. Cell proliferation was assessed by cell viability and the [3H] thymidine incorporation assay, and the redox state within the cells was examined by measuring reactive oxygen species (ROS) generation. The results demonstrated that PASMCs in high glucose (HG) grew, proliferated faster, and generated higher levels of superoxide anion (O2·−) and hydrogen peroxide (H2O2). The metabolomics of cells cultured in HG showed that the carbohydrate pathway, especially that of the upper glycolytic pathway metabolites, was influenced by the activation of the oxidation pathway: the pentose phosphate pathway (PPP). The amount of amino acids such as aspartate and glutathione reduced via HG, while glutathione disulfide, N6-Acetyl-L-lysine, glutamate, and 5-aminopentanoate increased. Lipids either as fatty acids or glycerophospholipids were downregulated in most of the metabolites, with the exception of docosatetraenoic acid and PG (16:0/16:1(9Z)). Purine and pyrimidine were influenced by hyperglycaemia following PPP oxidation. The results in addition showed that cells exposed to 25 mM of glucose were oxidatively stressed comparing to those cultured in five mM of glucose. Cholecalciferol (D3, or vitamin D) and tocopherol (vitamin E) were shown to restore the redox status of many metabolic pathways.

Abstract MP19: Smooth Muscle Cell Cytochrome B5 Reductase 3 Causes Heart Failure With Reduced Ejection Fraction Under Hypoxic Stress

Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Brittany G Durgin ◽  
Adam C Straub ◽  
Katherine C Wood ◽  
Scott A Hahn
Keyword(s):  
Heart Failure ◽  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Ejection Fraction ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Cytochrome B5 ◽  
Muscle Cells ◽  
Right Heart

Pulmonary hypertension causes increased pulmonary vascular resistance and right heart failure. Nitric oxide (NO) binds to its receptor soluble guanylyl cyclase (sGC) within vascular smooth muscle cells in its reduced heme (Fe 2+ ) form to increase intracellular cGMP production, activate protein kinase G signaling, and induce vessel relaxation. In pulmonary hypertension, endothelial damage leading to decreased NO bioavailability combined with oxidation of the sGC heme (Fe 3+ ) in vascular smooth muscle cells rendering it NO-insensitive results in vasonstriction. Notably, we have previously shown that cytochrome b5 reductase 3 (CYB5R3) in vascular smooth muscle cells is an sGC reductase (Fe 3+ to Fe 2+ ) that maintains NO-dependent vasodilation in vascular disease. We therefore hypothesized that CYB5R3 confers protection in pulmonary hypertension. To test this, we subjected smooth muscle cell-specific CYB5R3 knockout mice (SMC CYB5R3 KO) to 21 days of continuous hypoxia (10% O 2 ) and assessed vascular and cardiac function. We found that SMC CYB5R3 KO led to enhanced cardiac hypertrophy when compared to wild-type (WT) controls (n=8/ group). Specifically, SMC CYB5R3 KO mice had a larger right ventricle per tibia size, left ventricle mass, and Fulton index compared to WT (n=8/ group). Moreover, SMC CYB5R3 KO mice had a significantly impaired ejection fraction and fractional shortening, and increased left ventricular posterior wall pressure (n=3-5/group). No differences in right heart function or overall cardiac fibrosis were observed between groups (n=3-5/group). With respect to vascular function, hypoxic pulmonary arteries from SMC CYB5R3 KO mice also had a blunted response to sodium nitroprusside induced NO-dependent vasodilation though no difference in sGC activator BAY 58-2667 induced NO-independent vasodilation was observed as compared to WT (n=8-11/ group). No differences in pulmonary arterial sGC levels or medial area were observed between groups (n=6-7). Combined, these data implicate that loss of SMC CYB5R3 exacerbates cardiomyocyte hypertrophy and reduces cardiac function independent of pulmonary pressure differences.

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