scholarly journals Remodeling of Kv7.1 and Kv7.5 Expression in Vascular Tumors

2020 ◽  
Vol 21 (17) ◽  
pp. 6019 ◽  
Author(s):  
Clara Serrano-Novillo ◽  
Anna Oliveras ◽  
Joan Carles Ferreres ◽  
Enric Condom ◽  
Antonio Felipe
Keyword(s):  
Cell Cycle Progression ◽  
Vascular Tone ◽  
Neoplastic Cell ◽  
Vascular Tumors ◽  
Kv7 Channels ◽  
Cell Functions ◽  
Kv Channels ◽  
Voltage Dependent ◽  
Myocyte Proliferation ◽  
Different Origins

Voltage-dependent potassium (Kv) channels contribute to the excitability of nerves and muscles. In addition, Kv participates in several cell functions, including cell cycle progression and proliferation. Kv channel remodeling has been associated with neoplastic cell growth and cancer. Kv7 channels are expressed in blood vessels, and they participate in the maintenance of vascular tone and are implicated in myocyte proliferation. Although evidence links Kv7 remodeling to different types of cancer, its expression in vascular tumors has never been studied. Endothelium-derived vascular neoplasms range from indolent lesions to highly aggressive and metastasizing cancers. Here, we show that Kv7.1 and Kv7.5 are evenly distributed in tunicas as well as the endothelium of healthy veins and arteries. The layered structure of vessels is lost in vascular tumors. By studying eight vascular tumors with different origins and characteristics, we found that Kv7.1 and Kv7.5 expression was changed in vascular cancers. While both channels were generally downregulated, Kv7.5 expression was clearly correlated with neoplastic malignancy. The vascular tumors did not contract; therefore, the role of Kv7 channels is probably related to proliferation rather than controlling vascular tone. Our results identify vascular Kv7 channels as targets for cancer detection and anticancer therapies.

Tonic regulation of vascular tone by nitric oxide and chloride ions in rat isolated small coronary arteries

2000 ◽  
Vol 279 (6) ◽  
pp. H2604-H2611 ◽  
Author(s):  
Jonathan E. Graves ◽  
Iain A. Greenwood ◽  
William A. Large
Keyword(s):  
Nitric Oxide ◽  
Coronary Arteries ◽  
Vascular Tone ◽  
Physiological Saline ◽  
Chloride Ions ◽  
Bathing Solution ◽  
Contractile Mechanism ◽  
Mechanical Removal ◽  
Voltage Dependent ◽  
Physiological Saline Solution

We have investigated the involvement of Cl− in regulating vascular tone in rat isolated coronary arteries mounted on a small vessel myograph. Mechanical removal of the endothelium or inhibition of nitric oxide (NO) synthase with N ω-nitro-l-arginine methyl ester (l-NAME, 10−4 M) led to contraction of rat coronary arteries, and these contractions were sensitive to nicardipine (10−6 M). This suggests that release of NO tonically inhibits a contractile mechanism that involves voltage-dependent Ca2+ channels. In arteries contracted withl-NAME, switching the bathing solution to physiological saline solution with a reduced Cl− concentration potentiated the contraction. DIDS (5 × 10−6–3 × 10−4 M) caused relaxation of l-NAME-induced tension (IC50 = 55 ± 10 μM), providing evidence for a role of Cl−. SITS (10−5–5 × 10−4 M) did not affectl-NAME-induced tension, suggesting that DIDS is not acting by inhibition of anion exchange. Mechanical removal of the endothelium led to contraction of arteries, which was sensitive to DIDS (IC50 = 50 ± 8 μM) and was not affected by SITS. This study suggests that, in rat coronary arteries, NO tonically suppresses a contractile mechanism that involves a Cl−conductance.

Cooperative regulation of GSK-3 by muscarinic and PDGF receptors is associated with airway myocyte proliferation

2007 ◽  
Vol 293 (5) ◽  
pp. L1348-L1358 ◽  
Author(s):  
Reinoud Gosens ◽  
Gordon Dueck ◽  
Edward Rector ◽  
Raquel O. Nunes ◽  
William T. Gerthoffer ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Muscarinic Receptors ◽  
Cell Cycle Progression ◽  
Glycogen Synthase ◽  
Synergistic Effects ◽  
Inhibitory Function ◽  
Gf 109203X ◽  
Rb Phosphorylation ◽  
Myocyte Proliferation ◽  
Sb 216763

Muscarinic receptors and platelet-derived growth factor (PDGF) receptors synergistically induce proliferation of airway smooth muscle (ASM), but the pathways that regulate these effects are not yet completely identified. We hypothesized that glycogen synthase kinase-3 (GSK-3), a kinase that represses several promitogenic signaling pathways in its unphosphorylated form, is cooperatively inhibited by PDGF and muscarinic receptors in immortalized human ASM cell lines. PDGF or methacholine alone induced rapid GSK-3 phosphorylation. This phosphorylation was sustained only for PDGF; however, methacholine potentiated PDGF-induced sustained GSK-3 phosphorylation. Synergistic effects of methacholine also were observed on PDGF-induced retinoblastoma protein (Rb) phosphorylation and cell proliferation. Suppression of GSK-3 inhibitory function using SB 216763 also augmented PDGF-induced Rb phosphorylation and cell cycle progression; this synergy was similar in magnitude to that seen for methacholine with PDGF. GSK-3 phosphorylation induced by methacholine required PKC, since it was abolished by GF 109203X and Gö 6976; however, inhibition of PKC had no effect on cell responses to PDGF. PKC inhibition also specifically abolished the synergistic effect of methacholine on PDGF-induced GSK-3 phosphorylation and cell proliferation. Collectively, these results show that GSK-3 plays a key repressive role in ASM cell proliferation. Moreover, muscarinic receptors mediate PKC-dependent GSK-3 inhibition, and this appears to be a primary mechanism underpinning augmentation of PDGF-induced cell growth.

Vascular smooth muscle cell dysfunction in diabetes: nuclear receptors channel to relaxation

2016 ◽  
Vol 130 (20) ◽  
pp. 1837-1839 ◽  
Author(s):  
Geneviève Doyon ◽  
Dennis Bruemmer
Keyword(s):  
Cell Function ◽  
Vascular Dysfunction ◽  
Microvascular Disease ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Endothelial Cell Function ◽  
Cell Dysfunction ◽  
Kv Channels ◽  
Voltage Dependent ◽  
Patients With Diabetes

Endothelial dysfunction and impaired vascular relaxation represent a common cause of microvascular disease in patients with diabetes. Although multiple mechanisms underlying altered endothelial cell function in diabetes have been described, there is currently no specific and approved pharmacological treatment. In this edition of Clinical Science, Morales-Cano et al. characterize voltage-dependent K+ (Kv) channels as genes regulated by pharmacological activation of peroxisome proliferator-activated receptor-b/d (PPARb/d). Diabetes altered Kv channel function leading to impaired coronary artery relaxation, which was prevented by pharmacological activation of PPARb/d. These studies highlight an important mechanism of vascular dysfunction in diabetes and point to a potential approach for therapy, particularly considering that PPARb/d ligands have been developed and tested in small clinical trials.

scholarly journals Electrostatic Interaction of Internal Mg2+ with Membrane PIP2 Seen with KCNQ K+ Channels

2007 ◽  
Vol 130 (3) ◽  
pp. 241-256 ◽  
Author(s):  
Byung-Chang Suh ◽  
Bertil Hille
Keyword(s):  
Time Course ◽  
Inhibitory Effects ◽  
Response Curves ◽  
Pipette Solution ◽  
Current Time ◽  
Kv7 Channels ◽  
Cellular Processes ◽  
Polyvalent Cations ◽  
Voltage Dependent ◽  
Phosphatidylinositol 4

Activity of KCNQ (Kv7) channels requires binding of phosphatidylinositol 4,5-bisphosphate (PIP2) from the plasma membrane. We give evidence that Mg2+ and polyamines weaken the KCNQ channel–phospholipid interaction. Lowering internal Mg2+ augmented inward and outward KCNQ currents symmetrically, and raising Mg2+ reduced currents symmetrically. Polyvalent organic cations added to the pipette solution had similar effects. Their potency sequence followed the number of positive charges: putrescine (+2) < spermidine (+3) < spermine (+4) < neomycin (+6) < polylysine (≫+6). The inhibitory effects of Mg2+ were reversible with sequential whole-cell patching. Internal tetraethylammonium ion (TEA) gave classical voltage-dependent block of the pore with changes of the time course of K+ currents. The effect of polyvalent cations was simpler, symmetric, and without changes of current time course. Overexpression of phosphatidylinositol 4-phosphate 5-kinase Iγ to accelerate synthesis of PIP2 attenuated the sensitivity to polyvalent cations. We suggest that Mg2+ and other polycations reduce the currents by electrostatic binding to the negative charges of PIP2, competitively reducing the amount of free PIP2 available for interaction with channels. The dose–response curves could be modeled by a competition model that reduces the pool of free PIP2. This mechanism is likely to modulate many other PIP2-dependent ion channels and cellular processes.

scholarly journals Mechanisms of in utero cortisol effects on the newborn heart revealed by transcriptomic modeling

2019 ◽  
Vol 316 (4) ◽  
pp. R323-R337 ◽  
Author(s):  
Andrew Antolic ◽  
Mengchen Li ◽  
Elaine M. Richards ◽  
Celia W. Curtis ◽  
Charles E. Wood ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Perinatal Death ◽  
Interventricular Septum ◽  
Cardiac Metabolism ◽  
Metabolic Effects ◽  
Morphogenetic Protein ◽  
Short Term Exposure ◽  
And Function ◽  
Myocyte Proliferation

We have identified effects of elevated maternal cortisol (induced by maternal infusion 1 mg·kg−1·day−1) on fetal cardiac maturation and function using an ovine model. Whereas short-term exposure (115–130-day gestation) increased myocyte proliferation and Purkinje fiber apoptosis, infusions until birth caused bradycardia with increased incidence of arrhythmias at birth and increased perinatal death, despite normal fetal cortisol concentrations from 130 days to birth. Statistical modeling of the transcriptomic changes in hearts at 130 and 140 days suggested that maternal cortisol excess disrupts cardiac metabolism. In the current study, we modeled pathways in the left ventricle (LV) and interventricular septum (IVS) of newborn lambs after maternal cortisol infusion from 115 days to birth. In both LV and IVS the transcriptomic model indicated over-representation of cell cycle genes and suggested disruption of cell cycle progression. Pathways in the LV involved in cardiac architecture, including SMAD and bone morphogenetic protein ( BMP) were altered, and collagen deposition was increased. Pathways in IVS related to metabolism, calcium signaling, and the actin cytoskeleton were altered. Comparison of the effects of maternal cortisol excess to the effects of normal maturation from day 140 to birth revealed that only 20% of the genes changed in the LV were consistent with normal maturation, indicating that chronic elevation of maternal cortisol alters normal maturation of the fetal myocardium. These effects of maternal cortisol on the cardiac transcriptome, which may be secondary to metabolic effects, are consistent with cardiac remodeling and likely contribute to the adverse impact of maternal stress on perinatal cardiac function.

Inhibition by Imipramine of the Voltage-Dependent K+ Channel in Rabbit Coronary Arterial Smooth Muscle Cells

2020 ◽  
Vol 178 (2) ◽  
pp. 302-310
Author(s):  
Jin Ryeol An ◽  
Mi Seon Seo ◽  
Hee Seok Jung ◽  
Ryeon Heo ◽  
Minji Kang ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Dependent Manner ◽  
Arterial Smooth Muscle ◽  
Closed State ◽  
Kv Channels ◽  
State Dependent ◽  
Voltage Dependent ◽  
Arterial Smooth Muscle Cells

Abstract Imipramine, a tricyclic antidepressant, is used in the treatment of depressive disorders. However, the effect of imipramine on vascular ion channels is unclear. Therefore, using a patch-clamp technique we examined the effect of imipramine on voltage-dependent K+ (Kv) channels in freshly isolated rabbit coronary arterial smooth muscle cells. Kv channels were inhibited by imipramine in a concentration-dependent manner, with an IC50 value of 5.55 ± 1.24 µM and a Hill coefficient of 0.73 ± 0.1. Application of imipramine shifted the steady-state activation curve in the positive direction, indicating that imipramine-induced inhibition of Kv channels was mediated by influencing the voltage sensors of the channels. The recovery time constants from Kv-channel inactivation were increased in the presence of imipramine. Furthermore, the application of train pulses (of 1 or 2 Hz) progressively augmented the imipramine-induced inhibition of Kv channels, suggesting that the inhibitory effect of imipramine is use (state) dependent. The magnitude of Kv current inhibition by imipramine was similar during the first, second, and third depolarizing pulses. These results indicate that imipramine-induced inhibition of Kv channels mainly occurs in the closed state. The imipramine-mediated inhibition of Kv channels was associated with the Kv1.5 channel, not the Kv2.1 or Kv7 channel. Inhibition of Kv channels by imipramine caused vasoconstriction. From these results, we conclude that imipramine inhibits vascular Kv channels in a concentration- and use (closed-state)-dependent manner by changing their gating properties regardless of its own function.

scholarly journals Protein Acetylation and Acetyl Coenzyme A Metabolism in Budding Yeast

2014 ◽  
Vol 13 (12) ◽  
pp. 1472-1483 ◽  
Author(s):  
Luciano Galdieri ◽  
Tiantian Zhang ◽  
Daniella Rogerson ◽  
Rron Lleshi ◽  
Ales Vancura
Keyword(s):  
Cell Cycle Progression ◽  
Coenzyme A ◽  
Central Position ◽  
Metabolic State ◽  
Acetyl Coa ◽  
Cycle Progression ◽  
Acetyl Coenzyme A ◽  
Cell Functions ◽  
Physical Conditions ◽  
Acetyl Coenzyme

ABSTRACT Cells sense and appropriately respond to the physical conditions and availability of nutrients in their environment. This sensing of the environment and consequent cellular responses are orchestrated by a multitude of signaling pathways and typically involve changes in transcription and metabolism. Recent discoveries suggest that the signaling and transcription machineries are regulated by signals which are derived from metabolism and reflect the metabolic state of the cell. Acetyl coenzyme A (CoA) is a key metabolite that links metabolism with signaling, chromatin structure, and transcription. Acetyl-CoA is produced by glycolysis as well as other catabolic pathways and used as a substrate for the citric acid cycle and as a precursor in synthesis of fatty acids and steroids and in other anabolic pathways. This central position in metabolism endows acetyl-CoA with an important regulatory role. Acetyl-CoA serves as a substrate for lysine acetyltransferases (KATs), which catalyze the transfer of acetyl groups to the epsilon-amino groups of lysines in histones and many other proteins. Fluctuations in the concentration of acetyl-CoA, reflecting the metabolic state of the cell, are translated into dynamic protein acetylations that regulate a variety of cell functions, including transcription, replication, DNA repair, cell cycle progression, and aging. This review highlights the synthesis and homeostasis of acetyl-CoA and the regulation of transcriptional and signaling machineries in yeast by acetylation.

Protriptyline, a tricyclic antidepressant, inhibits voltage-dependent K+ channels in rabbit coronary arterial smooth muscle cells

2020 ◽  
Vol 52 (3) ◽  
pp. 320-327 ◽  
Author(s):  
Jin Ryeol An ◽  
Hojung Kang ◽  
Hongliang Li ◽  
Mi Seon Seo ◽  
Hee Seok Jung ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Steady State ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Tricyclic Antidepressant ◽  
Dependent Manner ◽  
Kv Channels ◽  
State Dependent ◽  
Voltage Dependent ◽  
Arterial Smooth Muscle Cells

Abstract In this study, we explore the inhibitory effects of protriptyline, a tricyclic antidepressant drug, on voltage-dependent K+ (Kv) channels of rabbit coronary arterial smooth muscle cells using a whole-cell patch clamp technique. Protriptyline inhibited the vascular Kv current in a concentration-dependent manner, with an IC50 value of 5.05 ± 0.97 μM and a Hill coefficient of 0.73 ± 0.04. Protriptyline did not affect the steady-state activation kinetics. However, the drug shifted the steady-state inactivation curve to the left, suggesting that protriptyline inhibited the Kv channels by changing their voltage sensitivity. Application of 20 repetitive train pulses (1 or 2 Hz) progressively increased the protriptyline-induced inhibition of the Kv current, suggesting that protriptyline inhibited Kv channels in a use (state)-dependent manner. The extent of Kv current inhibition by protriptyline was similar during the first, second, and third step pulses. These results suggest that protriptyline-induced inhibition of the Kv current mainly occurs principally in the closed state. The increase in the inactivation recovery time constant in the presence of protriptyline also supported use (state)-dependent inhibition of Kv channels by the drug. In the presence of the Kv1.5 inhibitor, protriptyline did not induce further inhibition of the Kv channels. However, pretreatment with a Kv2.1 or Kv7 inhibitor induced further inhibition of Kv current to a similar extent to that observed with protriptyline alone. Thus, we conclude that protriptyline inhibits the vascular Kv channels in a concentration- and use-dependent manner by changing their gating properties. Furthermore, protriptyline-induced inhibition of Kv channels mainly involves the Kv1.5.

Redox variants of NO (NO· and HNO) elicit vasorelaxation of resistance arteries via distinct mechanisms

2009 ◽  
Vol 296 (5) ◽  
pp. H1274-H1280 ◽  
Author(s):  
Joanne L. Favaloro ◽  
Barbara K. Kemp-Harper
Keyword(s):  
Vascular Tone ◽  
Soluble Guanylate Cyclase ◽  
Mesenteric Arteries ◽  
Resistance Arteries ◽  
Angeli's Salt ◽  
Voltage Dependent ◽  
Vasorelaxant Activity ◽  
Electron Reduction ◽  
Resting Tone ◽  
Redox Forms

The free radical form of nitric oxide (NO·) is a well-known mediator of vascular tone. What is not so well recognized is that NO· exists in several different redox forms. There is considerable evidence that NO· and its one-electron reduction product, nitroxyl (HNO), have pharmacologically distinct actions that extend into the regulation of the vasculature. The aim of this study was to compare the vasorelaxation mechanisms of HNO and NO·, including an examination of the ability of these redox variants to hyperpolarize and repolarize vascular smooth muscle cells from rat mesenteric arteries. The HNO donor Angeli's salt (0.1 nM–10 μM) caused a concentration-dependent hyperpolarization of vessels at resting tone and a simultaneous, concentration-dependent vasorelaxation and repolarization of vessels precontracted and depolarized with methoxamine. Both vasorelaxation and repolarization responses to Angeli's salt were significantly attenuated by both the HNO scavenger l-cysteine (3 mM) and the voltage-dependent K+ (Kv) channel inhibitor 4-aminopyridine (4-AP; 1 mM) and virtually abolished by the soluble guanylate cyclase (sGC) inhibitor 1 H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 10 μM) or 30 mM K+. In contrast, NO· (0.01–1 μM) repolarized arteries to a lesser extent than HNO, and these responses were resistant to inhibition by ODQ (10 μM) and 4-AP (1 mM). Blockade of Kv channels (1 mM 4-AP) also significantly inhibited the repolarization response to YC-1 (0.1–10 μM), confirming a role for sGC/cGMP in the activation of Kv channels in this preparation. We conclude that HNO causes vasorelaxation via a cGMP-dependent activation of Kv channels and that there are different profiles of vasorelaxant activity for the redox siblings HNO and NO·.

scholarly journals Common Principles of Voltage-Dependent Gating for Hv and Kv Channels

Neuron ◽  
2013 ◽  
Vol 77 (2) ◽  
pp. 214-216 ◽  
Author(s):  
Jeet Kalia ◽  
Kenton J. Swartz
Keyword(s):  
Kv Channels ◽  
Voltage Dependent
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