Alterations in a redox oxygen sensing mechanism in chronic hypoxia

2001 ◽  
Vol 90 (6) ◽  
pp. 2249-2256 ◽  
Author(s):  
H. L. Reeve ◽  
E. Michelakis ◽  
D. P. Nelson ◽  
E. K. Weir ◽  
S. L. Archer
Keyword(s):  
Smooth Muscle ◽  
Chronic Hypoxia ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Oxygen Species ◽  
Redox Sensor ◽  
Pulmonary Vasoconstriction ◽  
Activated Oxygen ◽  
Channel Expression ◽  
Pulmonary Arterial ◽  
Pulmonary Artery Smooth Muscle

The mechanism of acute hypoxic pulmonary vasoconstriction (HPV) may involve the inhibition of several voltage-gated K+channels in pulmonary artery smooth muscle cells. Changes in Po 2 can either be sensed directly by the channel(s) or be transmitted to the channel via a redox-based effector mechanism. In control lungs, hypoxia and rotenone acutely decrease production of activated oxygen species, inhibit K+channels, and cause constriction. Two-day and 3-wk chronic hypoxia (CH) resulted in a decrease in basal activated oxygen species levels, an increase in reduced glutathione, and loss of HPV and rotenone-induced constriction. In contrast, 4-aminopyridine- and KCl-mediated constrictions were preserved. After 3-wk CH, pulmonary arterial smooth muscle cell membrane potential was depolarized, K+ channel density was reduced, and acute hypoxic inhibition of whole cell K+ current was lost. In addition, Kv1.5 and Kv2.1 channel protein was decreased. These data suggest that chronic reduction of the cytosol occurs before changes in K+ channel expression. HPV may be attenuated in CH because of an impaired redox sensor.

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.

Mibefradil suppresses the proliferation of pulmonary artery smooth muscle cells

2016 ◽  
Vol 64 (1) ◽  
pp. 45-49 ◽  
Author(s):  
Hong-Hong Li ◽  
Li-Jian Xie ◽  
Ting-Ting Xiao ◽  
Min Huang ◽  
Jie Shen
Keyword(s):  
Smooth Muscle ◽  
Pulmonary Artery ◽  
Transient Receptor Potential ◽  
Critical Role ◽  
Receptor Potential ◽  
Channel Expression ◽  
Intracellular Ca ◽  
Pulmonary Arterial ◽  
Pulmonary Artery Smooth Muscle ◽  
Transient Receptor

Intracellular Ca2+ levels play a critical role in the regulation of vasodilation and vasoconstriction by stimulating pulmonary artery smooth muscle cell (PASMC) proliferation, which is important in the pathogenesis of pulmonary arterial hypertension (PAH); however, L-type Ca2+ channel antagonists are useful in only few patients with PAH. The present study sought to assess the effect of mibefradil, which blocks T-type Ca2+ channels, on PASMC proliferation and Ca2+ channel profile. Human PASMCs were stimulated with 25 ng/mL platelet-derived growth factor-BB (PDGF-BB) with and without 10 µM mibefradil or 100 nM sildenafil. After 48 or 72 h, PASMC proliferation and Ca2+ channel expression were assessed by MTT assays and western blot analysis, respectively. PDGF-BB-induced PASMC proliferation at 72 h (p<0.01), which was inhibited by both sildenafil and mibefradil (p<0.01). Transient receptor potential Ca2+ channel 6 (TRPC6) expression was significantly increased with PDGF-BB stimulation (p=0.009); however, no changes in TRPC1, TRPC3, CAV1.2, and CAV3.2 levels were observed. Although both TRPC1 and CAV1.2 expression levels were increased in PDGF-stimulated PASMCs on mibefradil and sildenafil treatment, it was not statistically significant (p=0.086 and 1.000, respectively). Mibefradil inhibits PDGF-BB-stimulated PASMC proliferation; however, the mechanism through which it functions remains to be determined. Further studies are required to elucidate the full therapeutic value of mibefradil for PAH.

Upregulation of Na+/Ca2+ exchanger contributes to the enhanced Ca2+ entry in pulmonary artery smooth muscle cells from patients with idiopathic pulmonary arterial hypertension

2007 ◽  
Vol 292 (6) ◽  
pp. C2297-C2305 ◽  
Author(s):  
Shen Zhang ◽  
Hui Dong ◽  
Lewis J. Rubin ◽  
Jason X.-J. Yuan
Keyword(s):  
Smooth Muscle ◽  
Pulmonary Arterial Hypertension ◽  
Pulmonary Artery ◽  
Arterial Hypertension ◽  
Smooth Muscle Cells ◽  
Idiopathic Pulmonary Arterial Hypertension ◽  
Reverse Mode ◽  
Pulmonary Vasoconstriction ◽  
Pulmonary Arterial ◽  
Pulmonary Artery Smooth Muscle

A rise in cytosolic Ca2+ concentration ([Ca2+]cyt) in pulmonary artery smooth muscle cells (PASMC) is a trigger for pulmonary vasoconstriction and a stimulus for PASMC proliferation and migration. Multiple mechanisms are involved in regulating [Ca2+]cyt in human PASMC. The resting [Ca2+]cyt and Ca2+ entry are both increased in PASMC from patients with idiopathic pulmonary arterial hypertension (IPAH), which is believed to be a critical mechanism for sustained pulmonary vasoconstriction and excessive pulmonary vascular remodeling in these patients. Here we report that protein expression of NCX1, an NCX family member of Na+/Ca2+ exchanger proteins is upregulated in PASMC from IPAH patients compared with PASMC from normal subjects and patients with other cardiopulmonary diseases. The Na+/Ca2+ exchanger operates in a forward (Ca2+ exit) and reverse (Ca2+ entry) mode. By activating the reverse mode of Na+/Ca2+ exchange, removal of extracellular Na+ caused a rapid increase in [Ca2+]cyt, which was significantly enhanced in IPAH PASMC compared with normal PASMC. Furthermore, passive depletion of intracellular Ca2+ stores using cyclopiazonic acid (10 μM) not only caused a rise in [Ca2+]cyt due to Ca2+ influx through store-operated Ca2+ channels but also mediated a rise in [Ca2+]cyt via the reverse mode of Na+/Ca2+ exchange. The upregulated NCX1 in IPAH PASMC led to an enhanced Ca2+ entry via the reverse mode of Na+/Ca2+ exchange, but did not accelerate Ca2+ extrusion via the forward mode of Na+/Ca2+ exchange. These observations indicate that the upregulated NCX1 and enhanced Ca2+ entry via the reverse mode of Na+/Ca2+ exchange are an additional mechanism responsible for the elevated [Ca2+]cyt in PASMC from IPAH patients.

scholarly journals Upregulation of IRF9 Contributes to Pulmonary Artery Smooth Muscle Cell Proliferation During Pulmonary Arterial Hypertension

2021 ◽  
Vol 12 ◽  
Author(s):  
Yong-Jie Chen ◽  
Yi Li ◽  
Xian Guo ◽  
Bo Huo ◽  
Yue Chen ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Smooth Muscle ◽  
Pulmonary Arterial Hypertension ◽  
Pulmonary Artery ◽  
Arterial Hypertension ◽  
Signaling Pathway ◽  
Chronic Hypoxia ◽  
Pathological Feature ◽  
Pulmonary Arterial ◽  
Pulmonary Artery Smooth Muscle

Abnormal proliferation of pulmonary artery smooth muscle cells (PASMCs) is a critical pathological feature in the pathogenesis of pulmonary arterial hypertension (PAH), but the regulatory mechanisms remain largely unknown. Herein, we demonstrated that interferon regulatory factor 9 (IRF9) accelerated PASMCs proliferation by regulating Prohibitin 1 (PHB1) expression and the AKT-GSK3β signaling pathway. Compared with control groups, the rats treated with chronic hypoxia (CH), monocrotaline (MCT) or sugen5416 combined with chronic hypoxia (SuHx), and mice challenged with CH had significantly thickened pulmonary arterioles and hyperproliferative PASMCs. More importantly, the protein level of IRF9 was found to be elevated in the thickened medial wall of the pulmonary arterioles in all of these PAH models. Notably, overexpression of IRF9 significantly promoted the proliferation of rat and human PASMCs, as evidenced by increased cell counts, EdU-positive cells and upregulated biomarkers of cell proliferation. In contrast, knockdown of IRF9 suppressed the proliferation of rat and human PASMCs. Mechanistically, IRF9 directly restrained PHB1 expression and interacted with AKT to inhibit the phosphorylation of AKT at thr308 site, which finally led to mitochondrial dysfunction and PASMC proliferation. Unsurprisingly, MK2206, a specific inhibitor of AKT, partially reversed the PASMC proliferation inhibited by IRF9 knockdown. Thus, our results suggested that elevation of IRF9 facilitates PASMC proliferation by regulating PHB1 expression and AKT signaling pathway to affect mitochondrial function during the development of PAH, which indicated that targeting IRF9 may serve as a novel strategy to delay the pathological progression of PAH.

scholarly journals MicroRNA-mediated downregulation of K+ channels in pulmonary arterial hypertension

2020 ◽  
Vol 318 (1) ◽  
pp. L10-L26 ◽  
Author(s):  
Aleksandra Babicheva ◽  
Ramon J. Ayon ◽  
Tengteng Zhao ◽  
Jose F. Ek Vitorin ◽  
Nicole M. Pohl ◽  
...  
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Pulmonary Vasoconstriction ◽  
Channel Expression ◽  
Pulmonary Arterial ◽  
Direct Target ◽  
Non Coding Rnas ◽  
Pulmonary Artery Smooth Muscle ◽  
And Function ◽  
Channel Currents

Downregulated expression of K+ channels and decreased K+ currents in pulmonary artery smooth muscle cells (PASMC) have been implicated in the development of sustained pulmonary vasoconstriction and vascular remodeling in patients with idiopathic pulmonary arterial hypertension (IPAH). However, it is unclear exactly how K+ channels are downregulated in IPAH-PASMC. MicroRNAs (miRNAs) are small non-coding RNAs that are capable of posttranscriptionally regulating gene expression by binding to the 3′-untranslated regions of their targeted mRNAs. Here, we report that specific miRNAs are responsible for the decreased K+ channel expression and function in IPAH-PASMC. We identified 3 miRNAs (miR-29b, miR-138, and miR-222) that were highly expressed in IPAH-PASMC in comparison to normal PASMC (>2.5-fold difference). Selectively upregulated miRNAs are correlated with the decreased expression and attenuated activity of K+ channels. Overexpression of miR-29b, miR-138, or miR-222 in normal PASMC significantly decreased whole cell K+ currents and downregulated voltage-gated K+ channel 1.5 (KV1.5/KCNA5) in normal PASMC. Inhibition of miR-29b in IPAH-PASMC completely recovered K+ channel function and KV1.5 expression, while miR-138 and miR-222 had a partial or no effect. Luciferase assays further revealed that KV1.5 is a direct target of miR-29b. Additionally, overexpression of miR-29b in normal PASMC decreased large-conductance Ca2+-activated K+ (BKCa) channel currents and downregulated BKCa channel β1 subunit (BKCaβ1 or KCNMB1) expression, while inhibition of miR-29b in IPAH-PASMC increased BKCa channel activity and BKCaβ1 levels. These data indicate upregulated miR-29b contributes at least partially to the attenuated function and expression of KV and BKCa channels in PASMC from patients with IPAH.

Diphenyleneiodonium inhibits both potassium and calcium currents in isolated pulmonary artery smooth muscle cells

1994 ◽  
Vol 76 (6) ◽  
pp. 2611-2615 ◽  
Author(s):  
E. K. Weir ◽  
C. N. Wyatt ◽  
H. L. Reeve ◽  
J. Huang ◽  
S. L. Archer ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Smooth Muscle ◽  
Nadph Oxidase ◽  
Smooth Muscle Cells ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Muscle Cells ◽  
Calcium Currents ◽  
Pulmonary Vasoconstriction ◽  
Pulmonary Artery Smooth Muscle ◽  
Isolated Pulmonary Artery

Diphenyleneiodonium (DPI) blocks hypoxic vasoconstriction in the pulmonary vasculature. Because one of the actions of DPI is the inhibition of NADPH oxidase, this has led to the suggestion that NADPH oxidase acts as an oxygen tension sensor in pulmonary smooth muscle cells. We investigated the effects of DPI on potassium and calcium currents in freshly isolated pulmonary artery smooth muscle cells by using whole cell patch-clamp recordings, since these ionic currents are known to be involved in hypoxic pulmonary vasoconstriction. DPI (3 and 10 microM) reversibly inhibited potassium currents, and in its presence, residual currents appeared markedly more transient than under control conditions. The actions of DPI could not be reversed by 4.4 mM hydrogen peroxide, the product of NADPH oxidase. Calcium channel currents were also reversibly inhibited by 3 microM DPI. Thus DPI is a nonselective blocker of ionic channels in pulmonary smooth muscle cells, and its mechanism of action does not appear to involve inhibition of hydrogen peroxide formation. The ability of DPI to block calcium currents can explain its inhibition of hypoxic pulmonary vasoconstriction.

Direct role for potassium channel inhibition in hypoxic pulmonary vasoconstriction

1992 ◽  
Vol 262 (4) ◽  
pp. C882-C890 ◽  
Author(s):  
J. M. Post ◽  
J. R. Hume ◽  
S. L. Archer ◽  
E. K. Weir
Keyword(s):  
Smooth Muscle ◽  
Pulmonary Artery ◽  
Smooth Muscle Cells ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
K Channel ◽  
Pulmonary Vasoconstriction ◽  
Channel Inhibition ◽  
Pulmonary Arterial ◽  
Arterial Smooth Muscle Cells ◽  
K Currents

Cellular mechanisms responsible for hypoxic pulmonary vasoconstriction were investigated in pulmonary arterial cells, isolated perfused lung, and pulmonary artery rings. Three K+ channel antagonists, Leiurus quinquestriatus venom, tetraethylammonium, and 4-aminopyridine, mimicked the effects of hypoxia in isolated lung and arterial rings by increasing pulmonary artery pressure and tension and also inhibited whole cell K+ currents in isolated pulmonary arterial cells. Reduction of oxygen tension from normoxic to hypoxic levels directly inhibited K+ currents and caused membrane depolarization in isolated canine pulmonary arterial smooth muscle cells but not in canine renal arterial smooth muscle cells. Nisoldipine or high buffering of intracellular Ca2+ concentration with [1,2-bis(2)aminophenoxy] ethane-N,N,N',N'-tetraacetic acid prevented hypoxic inhibition of K+ current, suggesting that a Ca(2+)-sensitive K+ channel may be responsible for the hypoxic response. These results indicate that K+ channel inhibition may be a key event that links hypoxia to pulmonary vasoconstriction by causing membrane depolarization and subsequent Ca2+ entry.

TIGAR reduces smooth muscle cell autophagy to prevent pulmonary hypertension

2020 ◽  
Vol 319 (5) ◽  
pp. H1087-H1096
Author(s):  
Ryoetsu Yamanaka ◽  
Atsushi Hoshino ◽  
Kuniyoshi Fukai ◽  
Ryota Urata ◽  
Yoshito Minami ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Refractory Disease ◽  
Oxygen Species ◽  
Downstream Target ◽  
Promising Therapeutic Target ◽  
Pulmonary Arterial ◽  
Pulmonary Artery Smooth Muscle ◽  
Human Pulmonary Artery ◽  
And Migration ◽  
Proliferation And Migration

Pulmonary arterial hypertension is a refractory disease. TP53-induced glycolysis and apoptosis regulator (TIGAR) is a downstream target of p53 and exhibits functions inhibiting autophagy and reactive oxygen species (ROS). By using TIGAR-deficient knockout mice and human pulmonary artery smooth muscle cells, we found that TIGAR suppressed the proliferation and migration of PASMCs via inhibiting autophagy and ROS and, therefore, improved hypoxia-induced PH. TIGAR will be a promising therapeutic target for PAH.

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