scholarly journals Expression of Kv4.2 and Kv4.3 potassium channels in human umbilical veins from normal, diabetic and hypertensive pregnancies

2022 ◽  
pp. 5-5
Author(s):  
Vladimir Djokic ◽  
Milos Gostimirovic ◽  
Jovana Rajkovic ◽  
Jelena Rakocevic ◽  
Milica Labudovic-Borovic ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Potassium Channels ◽  
Western Blot ◽  
Umbilical Vein ◽  
Smooth Muscles ◽  
Local Environment ◽  
Similar Expression Pattern ◽  
Fetal Oxygenation ◽  
Frequency Of Action Potentials ◽  
And Function

Objective: A substantial line of evidence indicates that Kv4.2 and Kv4.3 channels are the major components of rapid transient-outward potassium currents (A-type currents). It is speculated that those currents may be involved in the maintenance of the membrane potential, as well as in the regulation of propagation and frequency of action potentials. However, very little is known about the presence and function of A-type currents in human vascular smooth muscles such as human umbilical vein (HUV). Having in mind its crucial role in the proper fetal oxygenation the aim of the study was to determine whether Kv4.2 and Kv4.3 potassium channels are present in HUV smooth muscle and to investigate potential alterations of their expression during maternal pathological conditions - gestational diabetes mellitus (GDM) and pregnancy-induced hypertension (PIH). Materials and methods: Healthy, diabetic and hypertensive pregnancies were subjects of this investigation. Each group was consisted of 6 HUV samples obtained from 6 normal pregnancies, 6 pregnancies with GDM, and 6 pregnancies with PIH. After pharmacology analysis, immunohistochemistry and Western blot were performed. Results: Immunohistochemistry revealed similar expression pattern of both, Kv4.2 and Kv4.3 subunits, in HUV smooth muscle in all groups of patients. Results obtained by Western blot were in agreement with immunohistochemical staining. The expression of Kv4.2 and Kv4.3 subunits was not significantly different between the groups. Conclusion: Collectively, this is the first study that demonstrated presence of Kv4.2 and Kv4.3 potassium channels in the HUV smooth muscle and their preservation during the course of GDM and PIH. These channels are most likely major components of rapid A-type currents that may be relevant for maternal-fetus blood flow and hence fetal development. Also, they may represent sensors for detecting hemodynamic and/or metabolic changes in the local environment.

Are gap junctions necessary for cell-to-cell coupling of smooth muscle?: an update

1992 ◽  
Vol 70 (4) ◽  
pp. 481-490 ◽  
Author(s):  
R. E. Garfield ◽  
G. Thilander ◽  
M. G. Blennerhassett ◽  
N. Sakai
Keyword(s):  
Smooth Muscle ◽  
Gap Junctions ◽  
Current Knowledge ◽  
Smooth Muscles ◽  
Cell Communication ◽  
Circular Muscle ◽  
Cell Coupling ◽  
And Function ◽  
Longitudinal Layer ◽  
Cell Cell

Earlier, it was questioned whether gap junctions (GJs) were necessary for cell–cell communication in smooth muscle, and GJs were not seen in some smooth muscles. We reexamined this question in the myometrium and in intestinal smooth muscle, in light of current knowledge of the presence and function of GJs. In the uterus, numerous studies show that an increase in GJ number is associated with the onset of delivery and is required for effective parturition. In all cases, this increase in GJ number and the changes in uterine contractility were correlated with increased electrical and metabolic coupling. Evidence for the much smaller, but detectable, degree of electrical coupling in the preterm uterus is explained by the small (but again detectable) number of GJs present. In the intestine, GJs are readily detected in the circular muscle layer but have not been described in the adjacent longitudinal layer. While our immunohistochemical studies failed to detect GJs in the longitudinal layer, this may not be adequate to prove their absence. Therefore, current knowledge of GJ number and function is adequate to explain cell–cell coupling in the uterus. Although it remains uncertain whether GJs are absent from the longitudinal muscle of the intestine, there is no definitive evidence that cell–cell coupling can occur by means other than GJs.Key words: gap junctions, myometrium, connexins, smooth muscle, cell communication.

Pregnancy-induced hypertension decreases Kv1.3 potassium channel expression and function in human umbilical vein smooth muscle

2020 ◽  
Vol 882 ◽  
pp. 173281 ◽  
Author(s):  
Vladimir Djokic ◽  
Svetlana Jankovic ◽  
Milica Labudovic-Borovic ◽  
Jelena Rakocevic ◽  
Jelena Stanisic ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Potassium Channel ◽  
Umbilical Vein ◽  
Pregnancy Induced Hypertension ◽  
Human Umbilical Vein ◽  
Induced Hypertension ◽  
Channel Expression ◽  
And Function

Smooth muscle intracellular pH: measurement, regulation, and function

1988 ◽  
Vol 254 (2) ◽  
pp. C213-C225 ◽  
Author(s):  
S. Wray
Keyword(s):  
Smooth Muscle ◽  
Intracellular Ph ◽  
Smooth Muscles ◽  
Muscle Membrane ◽  
Resonance Spectroscopy ◽  
Striated Muscles ◽  
Needed Information ◽  
Smooth Muscle Membrane ◽  
Muscle Types ◽  
And Function

Smooth muscle performs many functions that are essential for the normal working of the human body. Changes in pH are thought to affect many aspects of smooth muscle. Despite this, until recently little was known about either intracellular pH (pHi) values or pHi regulation in smooth muscle. Recent work measuring pHi with either microelectrodes or nuclear magnetic resonance spectroscopy is now providing some of this much needed information for smooth muscles. From these studies, it can be concluded tentatively that pHi is the same in different smooth muscles, approximately 7.06 (37 degrees C). This value is very close to those obtained in cardiac and skeletal muscle. It is clear that H+ is not in equilibrium across the smooth muscle membrane; i.e., pHi is regulated. Preliminary results in smooth muscle suggest that certain aspects of this regulation are different from that described for other muscle types. Changes in pHi have been found to produce marked effects on contraction in smooth muscle. Of particular interest is the fact that, unlike striated muscles, some smooth muscles can product more force during an intracellular acidification.

Assembly and Activation of the Intrinsic Fibrinolytic Pathway on the Surface of Human Endothelial Cells in Culture

1995 ◽  
Vol 74 (02) ◽  
pp. 698-703 ◽  
Author(s):  
Catherine Lenich ◽  
Ralph Pannell ◽  
Victor Gurewich
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Factor Xii ◽  
Plasminogen Activation ◽  
High Molecular Weight Kininogen ◽  
Human Endothelial Cells ◽  
Intrinsic Pathway ◽  
Local Fibrinolysis ◽  
Umbilical Vein Endothelial Cells ◽  
And Function

SummaryFactor XII has long been implicated in the intrinsic pathway of fibrinolysis, but the mechanism by which it triggers plasminogen activation and targets fibrinolysis has not been established. In the present study, the assembly and function of activated Factor XII (F.XIIa), prourokinase (pro-u-PA), high molecular weight kininogen (H-kininogen), and prekallikrein on human umbilical vein endothelial cells (HUVEC) was investigated. 125I-prekallikrein was shown to bind to HUVEC via receptor-bound H-kininogen in the presence of 50 μM ZnCl2. After the addition of F.XIIa, 78% of the 125I-prekallikrein initially bound to HUVEC was converted to 125I-kallikrein. However, only 6% of the HUVEC-bound 125I-pro-u-PA was thereby activated. This discrepancy was shown to be related to rapid dissociation (>50% within 15 min) of prekallikrein/kallikrein, but not pro-u-PA, from HUVEC. Increasing the level of cell-bound kallikrein increased the portion of cell-bound pro-u-PA activated, indicating that their co-localization was important for this pathway. Finally, F.XIIa was shown to trigger plasminogen activation on HUVEC via this pathway. This assembly of reactants on the endothelium suggests a mechanism whereby local fibrinolysis may be triggered by blood coagulation.

scholarly journals Quercetin relaxes human gastric smooth muscles directly through ATP‐sensitive potassium channels and not depending on the nitric oxide pathway

2021 ◽  
Author(s):  
Beata Modzelewska ◽  
Krzysztof Drygalski ◽  
Tomasz Kleszczewski ◽  
Andrzej Chomentowski ◽  
Krzysztof Koryciński ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Potassium Channels ◽  
Smooth Muscles ◽  
Nitric Oxide Pathway

scholarly journals Influence of layer separation on the determination of stomach smooth muscle properties

2021 ◽  
Author(s):  
Mischa Borsdorf ◽  
Markus Böl ◽  
Tobias Siebert
Keyword(s):  
Smooth Muscle ◽  
Muscle Fibers ◽  
Smooth Muscles ◽  
Muscle Layer ◽  
Uniaxial Tensile ◽  
Muscle Properties ◽  
Layer Separation ◽  
Isotonic Contractions ◽  
Longitudinal Layer

AbstractUniaxial tensile experiments are a standard method to determine the contractile properties of smooth muscles. Smooth muscle strips from organs of the urogenital and gastrointestinal tract contain multiple muscle layers with different muscle fiber orientations, which are frequently not separated for the experiments. During strip activation, these muscle fibers contract in deviant orientations from the force-measuring axis, affecting the biomechanical characteristics of the tissue strips. This study aimed to investigate the influence of muscle layer separation on the determination of smooth muscle properties. Smooth muscle strips, consisting of longitudinal and circumferential muscle layers (whole-muscle strips [WMS]), and smooth muscle strips, consisting of only the circumferential muscle layer (separated layer strips [SLS]), have been prepared from the fundus of the porcine stomach. Strips were mounted with muscle fibers of the circumferential layer inline with the force-measuring axis of the uniaxial testing setup. The force–length (FLR) and force–velocity relationships (FVR) were determined through a series of isometric and isotonic contractions, respectively. Muscle layer separation revealed no changes in the FLR. However, the SLS exhibited a higher maximal shortening velocity and a lower curvature factor than WMS. During WMS activation, the transversally oriented muscle fibers of the longitudinal layer shortened, resulting in a narrowing of this layer. Expecting volume constancy of muscle tissue, this narrowing leads to a lengthening of the longitudinal layer, which counteracted the shortening of the circumferential layer during isotonic contractions. Consequently, the shortening velocities of the WMS were decreased significantly. This effect was stronger at high shortening velocities.

scholarly journals LncRNA XIST regulates atherosclerosis progression in ox-LDL-induced HUVECs

Open Medicine ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. 117-127
Author(s):  
Hongmei Gao ◽  
Zhaohui Guo
Keyword(s):  
Smooth Muscle ◽  
Muscle Protein ◽  
Umbilical Vein ◽  
Smooth Muscle Actin ◽  
Quantitative Polymerase Chain Reaction ◽  
Density Lipoprotein ◽  
Inflammatory Factors ◽  
Luciferase Reporter ◽  
Western Blot Assay ◽  
Lactate Dehydrogenase Activity

Abstract Long noncoding RNAs (lncRNAs) have been verified as vital regulators in human disease, including atherosclerosis. However, the precise role of X-inactive-specific transcript (XIST) in atherosclerosis remains unclear. The proliferation and apoptosis of human umbilical vein endothelial cells (HUVECs) exposed to low-density lipoprotein (ox-LDL) were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazol-3-ium bromide, and flow cytometry assays, correspondingly. The western blot assay was used to quantify protein expression. Lactate dehydrogenase activity and the concentrations of inflammatory factors were measured by matched kits. The real-time quantitative polymerase chain reaction (qPCR) was used to determine α-smooth muscle actin, smooth muscle protein 22-α, XIST, miR-98-5p, and pregnancy-associated plasma protein A (PAPPA) levels in HUVECs. The relationship among XIST, miR-98-5p, and PAPPA was analyzed by dual-luciferase reporter, RNA immunoprecipitation, and RNA pull-down assays. We found ox-LDL repressed proliferation and induced inflammation and apoptosis in HUVECs. Loss-of-functional experiment suggested that the downregulation of XIST overturned the ox-LDL-induced effects on HUVECs. Additionally, overexpression of miR-98-5p-induced effects on ox-LDL-stimulated HUVECs was abolished by upregulation of XIST. However, silencing of miR-98-5p strengthened the ox-LDL-induced effects on HUVECs by increasing expression of PAPPA. Mechanistically, XIST could regulate PAPPA expression in ox-LDL-induced HUVECs by sponging miR-98-5p, providing understanding for atherosclerosis.

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