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Stylianou N, Sebina I, Matigian N, Monkman J, Doehler H, Röhl J, Allenby M, Nam A, Pan L, Rockstroh A, Sadeghirad H, Chung K, Sobanski T, O'Byrne K, Almeida ACSF, Rebutini PZ, Machado‐Souza C, Stonoga ETS, Warkiani ME, Salomon C, Short K, McClements L, de Noronha L, Huang R, Belz GT, Souza‐Fonseca‐Guimaraes F, Clifton V, Kulasinghe A. Whole transcriptome profiling of placental pathobiology in SARS-CoV-2 pregnancies identifies placental dysfunction signatures. Clin Transl Immunology 2024; 13:e1488. [PMID: 38322491 PMCID: PMC10846628 DOI: 10.1002/cti2.1488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 01/10/2024] [Accepted: 01/18/2024] [Indexed: 02/08/2024] Open
Abstract
Objectives Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus infection in pregnancy is associated with higher incidence of placental dysfunction, referred to by a few studies as a 'preeclampsia-like syndrome'. However, the mechanisms underpinning SARS-CoV-2-induced placental malfunction are still unclear. Here, we investigated whether the transcriptional architecture of the placenta is altered in response to SARS-CoV-2 infection. Methods We utilised whole-transcriptome, digital spatial profiling, to examine gene expression patterns in placental tissues from participants who contracted SARS-CoV-2 in the third trimester of their pregnancy (n = 7) and those collected prior to the start of the coronavirus disease 2019 (COVID-19) pandemic (n = 9). Results Through comprehensive spatial transcriptomic analyses of the trophoblast and villous core stromal cell subpopulations in the placenta, we identified SARS-CoV-2 to promote signatures associated with hypoxia and placental dysfunction. Notably, genes associated with vasodilation (NOS3), oxidative stress (GDF15, CRH) and preeclampsia (FLT1, EGFR, KISS1, PAPPA2) were enriched with SARS-CoV-2. Pathways related to increased nutrient uptake, vascular tension, hypertension and inflammation were also enriched in SARS-CoV-2 samples compared to uninfected controls. Conclusions Our findings demonstrate the utility of spatially resolved transcriptomic analysis in defining the underlying pathogenic mechanisms of SARS-CoV-2 in pregnancy, particularly its role in placental dysfunction. Furthermore, this study highlights the significance of digital spatial profiling in mapping the intricate crosstalk between trophoblasts and villous core stromal cells, thus shedding light on pathways associated with placental dysfunction in pregnancies with SARS-CoV-2 infection.
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Affiliation(s)
- Nataly Stylianou
- Australian Prostate Cancer Research Centre – Queensland, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Faculty of HealthQueensland University of TechnologyBrisbaneQLDAustralia
| | - Ismail Sebina
- Frazer Institute, Faculty of MedicineThe University of QueenslandBrisbaneQLDAustralia
| | | | - James Monkman
- Frazer Institute, Faculty of MedicineThe University of QueenslandBrisbaneQLDAustralia
| | - Hadeel Doehler
- Australian Prostate Cancer Research Centre – Queensland, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Faculty of HealthQueensland University of TechnologyBrisbaneQLDAustralia
| | - Joan Röhl
- Faculty of Health Sciences and MedicineBond UniversityRobinaQLDAustralia
| | - Mark Allenby
- BioMimetic Systems Engineering Lab, School of Chemical EngineeringUniversity of Queensland (UQ)St LuciaQLDAustralia
| | - Andy Nam
- Nanostring Technologies, Inc.SeattleWAUSA
| | - Liuliu Pan
- Nanostring Technologies, Inc.SeattleWAUSA
| | - Anja Rockstroh
- Australian Prostate Cancer Research Centre – Queensland, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Faculty of HealthQueensland University of TechnologyBrisbaneQLDAustralia
| | - Habib Sadeghirad
- Frazer Institute, Faculty of MedicineThe University of QueenslandBrisbaneQLDAustralia
| | - Kimberly Chung
- Frazer Institute, Faculty of MedicineThe University of QueenslandBrisbaneQLDAustralia
| | - Thais Sobanski
- Australian Prostate Cancer Research Centre – Queensland, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Faculty of HealthQueensland University of TechnologyBrisbaneQLDAustralia
| | - Ken O'Byrne
- Princess Alexandra HospitalWoolloongabbaQLDAustralia
| | | | - Patricia Zadorosnei Rebutini
- Postgraduate Program of Health Sciences, School of MedicinePontifícia Universidade Católica do Paraná ´ –PUCPRCuritibaBrazil
| | - Cleber Machado‐Souza
- Postgraduate Program in Biotechnology Applied in Health of Children and AdolescentInstituto de Pesquisa Pelé Pequeno Príncipe, Faculdades Pequeno PríncipeCuritibaBrazil
| | | | - Majid E Warkiani
- School of Life Sciences & Institute for Biomedical Materials and Devices, Faculty of ScienceUniversity of Technology SydneySydneyNSWAustralia
| | - Carlos Salomon
- Exosome Biology Laboratory, Centre for Clinical Diagnostics, University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Faculty of MedicineThe University of QueenslandBrisbaneQLDAustralia
| | - Kirsty Short
- School of Chemistry and Molecular Biosciences, Faculty of ScienceThe University of QueenslandSt LuciaQLDAustralia
| | - Lana McClements
- School of Life Sciences & Institute for Biomedical Materials and Devices, Faculty of ScienceUniversity of Technology SydneySydneyNSWAustralia
| | - Lucia de Noronha
- Postgraduate Program of Health Sciences, School of MedicinePontifícia Universidade Católica do Paraná ´ –PUCPRCuritibaBrazil
| | - Ruby Huang
- School of Medicine, College of MedicineNational Taiwan UniversityTaipeiTaiwan
| | - Gabrielle T Belz
- Frazer Institute, Faculty of MedicineThe University of QueenslandBrisbaneQLDAustralia
| | | | - Vicki Clifton
- Mater Medical Research InstituteUniversity of QueenslandBrisbaneQLDAustralia
| | - Arutha Kulasinghe
- Frazer Institute, Faculty of MedicineThe University of QueenslandBrisbaneQLDAustralia
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Albertini L, Ezekian J, Care M, Silversides C, Sermer M, Gollob MH, Spears D. Assessment of Severity of Long QT Syndrome Phenotype and Risk of Fetal Death. J Am Heart Assoc 2023; 12:e029407. [PMID: 38014677 PMCID: PMC10727344 DOI: 10.1161/jaha.122.029407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 10/30/2023] [Indexed: 11/29/2023]
Abstract
BACKGROUND It has been postulated that long QT syndrome (LQTS) can cause fetal loss through putative adverse effects of the channelopathy on placenta and myometrial function. The authors aimed to describe the fetal death rate in a population of pregnant women with long QT syndrome and investigate whether women with more severe phenotype had worse fetal outcomes. METHODS AND RESULTS The authors retrospectively evaluated fetal outcomes of 64 pregnancies from 23 women with long QT syndrome followed during pregnancy in a tertiary pregnancy and heart disease program. Thirteen of 64 pregnancies (20%) resulted in a fetal loss, 12 miscarriages (19%), and 1 stillbirth (1.6%). Baseline maternal characteristics, including age and use of β-blockers, did not differ between women who experienced a fetal death or not. Maternal corrected QT interval (QTc) was significantly longer in pregnancies that resulted in fetal death compared with live births (median, 518 ms [interquartile range (IQR), 482-519 ms] versus 479 ms [IQR, 454-496 ms], P<0.001). Mothers treated with β-blockers had babies born at term with lower birth weight compared with untreated women (2973±298 g versus 3470±338 g, P=0.002). In addition, the birth weight of babies born at term to treated women with QTc >500 ms was significantly lower compared with women with QTc <500 ms (2783±283 g versus 3084±256 g, P=0.029). CONCLUSIONS Women with long QT syndrome with more severe phenotypes have a higher incidence of fetal death. Maternal QTc is longer in pregnancies that result in fetal loss, and the birth weight of babies born to patients taking β-blockers with a QTc >500 ms is lower, suggesting that patients with more marked phenotype may experience worse fetal outcomes.
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Affiliation(s)
- Lisa Albertini
- Division of Cardiology, Electrophysiology, Toronto General HospitalUniversity Health Network TorontoTorontoOntarioCanada
| | - Jordan Ezekian
- Division of CardiologyThe Hospital for Sick ChildrenTorontoOntarioCanada
| | - Melanie Care
- Division of Cardiology, Electrophysiology, Toronto General HospitalUniversity Health Network TorontoTorontoOntarioCanada
| | - Candice Silversides
- Department of Medicine, Division of CardiologyUniversity of Toronto Pregnancy and Heart Disease Program and Obstetric Medicine Program, Mount Sinai and Toronto General HospitalsTorontoOntarioCanada
| | - Mathew Sermer
- Department of Obstetrics and GynaecologyMount Sinai HospitalTorontoOntarioCanada
| | - Michael H. Gollob
- Division of Cardiology, Electrophysiology, Toronto General HospitalUniversity Health Network TorontoTorontoOntarioCanada
| | - Danna Spears
- Division of Cardiology, Electrophysiology, Toronto General HospitalUniversity Health Network TorontoTorontoOntarioCanada
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3
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Baldwin SN, Jepps TA, Greenwood IA. Cycling matters: Sex hormone regulation of vascular potassium channels. Channels (Austin) 2023; 17:2217637. [PMID: 37243715 PMCID: PMC10228406 DOI: 10.1080/19336950.2023.2217637] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 05/07/2023] [Accepted: 05/19/2023] [Indexed: 05/29/2023] Open
Abstract
Sex hormones and the reproductive cycle (estrus in rodents and menstrual in humans) have a known impact on arterial function. In spite of this, sex hormones and the estrus/menstrual cycle are often neglected experimental factors in vascular basic preclinical scientific research. Recent research by our own laboratory indicates that cyclical changes in serum concentrations of sex -hormones across the rat estrus cycle, primary estradiol, have significant consequences for the subcellular trafficking and function of KV. Vascular potassium channels, including KV, are essential components of vascular reactivity. Our study represents a small part of a growing field of literature aimed at determining the role of sex hormones in regulating arterial ion channel function. This review covers key findings describing the current understanding of sex hormone regulation of vascular potassium channels, with a focus on KV channels. Further, we highlight areas of research where the estrus cycle should be considered in future studies to determine the consequences of physiological oscillations in concentrations of sex hormones on vascular potassium channel function.
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Affiliation(s)
- Samuel N Baldwin
- Vascular Biology Group, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas A Jepps
- Vascular Biology Group, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Iain A Greenwood
- Vascular Biology Research Centre, Institute of Molecular and Clinical Sciences, St George’s University of London, London, UK
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Julian CG, Houck JA, Fallahi S, Lazo-Vega L, Matarazzo CJ, Diamond B, Miranda-Garrido V, Krause BJ, Moore LG, Shortt JA, Toledo-Jaldin L, Lorca RA. Altered placental ion channel gene expression in preeclamptic high-altitude pregnancies. Physiol Genomics 2023; 55:357-367. [PMID: 37458464 PMCID: PMC10642922 DOI: 10.1152/physiolgenomics.00013.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 06/12/2023] [Accepted: 07/06/2023] [Indexed: 08/12/2023] Open
Abstract
High-altitude (>2,500 m) residence increases the risk of pregnancy vascular disorders such as fetal growth restriction and preeclampsia, each characterized by impaired placental function. Genetic attributes of highland ancestry confer relative protection against vascular disorders of pregnancy at high altitudes. Although ion channels have been implicated in placental function regulation, neither their expression in high-altitude placentas nor their relationship to high-altitude preeclampsia has been determined. Here, we measured the expression of 26 ion-channel genes in placentas from preeclampsia cases and normotensive controls in La Paz, Bolivia (3,850 m). In addition, we correlated gene transcription to maternal and infant ancestry proportions. Gene expression was assessed by PCR, genetic ancestry evaluated by ADMIXTURE, and ion channel proteins localized by immunofluorescence. In preeclamptic placentas, 11 genes were downregulated (ABCC9, ATP2A2, CACNA1C, KCNE1, KCNJ8, KCNK3, KCNMA1, KCNQ1, KCNQ4, PKD2, and TRPV6) and two were upregulated (KCNQ3 and SCNN1G). KCNE1 expression was positively correlated with high-altitude Amerindian ancestry and negatively correlated with non-high altitude. SCNN1G was negatively correlated with African ancestry, despite minimal African admixture. Most ion channels were localized in syncytiotrophoblasts (Cav1.2, TRPP2, TRPV6, and Kv7.1), whereas expression of Kv7.4 was primarily in microvillous membranes, Kir6.1 in chorionic plate and fetal vessels, and MinK in stromal cells. Our findings suggest a role for differential placental ion channel expression in the development of preeclampsia. Functional studies are needed to determine processes affected by these ion channels in the placenta and whether therapies directed at modulating their activity could influence the onset or severity of preeclampsia.
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Affiliation(s)
- Colleen G Julian
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Julie A Houck
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Sahand Fallahi
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Litzi Lazo-Vega
- Department of Obstetrics and Gynecology, Hospital Materno-Infantil, La Paz, Bolivia
| | - Christopher J Matarazzo
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Breea Diamond
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | | | - Bernardo J Krause
- Instituto de Ciencias de la Salud, Universidad de O'Higgins, Rancagua, Chile
| | - Lorna G Moore
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Jonathan A Shortt
- Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Lilian Toledo-Jaldin
- Department of Obstetrics and Gynecology, Hospital Materno-Infantil, La Paz, Bolivia
| | - Ramón A Lorca
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
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5
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Cáceres D, Ochoa M, González-Ortiz M, Bravo K, Eugenín J. Effects of Prenatal Cannabinoids Exposure upon Placenta and Development of Respiratory Neural Circuits. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1428:199-232. [PMID: 37466775 DOI: 10.1007/978-3-031-32554-0_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
Cannabis use has risen dangerously during pregnancy in the face of incipient therapeutic use and a growing perception of safety. The main psychoactive compound of the Cannabis sativa plant is the phytocannabinoid delta-9-tetrahydrocannabinol (A-9 THC), and its status as a teratogen is controversial. THC and its endogenous analogues, anandamide (AEA) and 2-AG, exert their actions through specific receptors (eCBr) that activate intracellular signaling pathways. CB1r and CB2r, also called classic cannabinoid receptors, together with their endogenous ligands and the enzymes that synthesize and degrade them, constitute the endocannabinoid system. This system is distributed ubiquitously in various central and peripheral tissues. Although the endocannabinoid system's most studied role is controlling the release of neurotransmitters in the central nervous system, the study of long-term exposure to cannabinoids on fetal development is not well known and is vital for understanding environmental or pathological embryo-fetal or postnatal conditions. Prenatal exposure to cannabinoids in animal models has induced changes in placental and embryo-fetal organs. Particularly, cannabinoids could influence both neural and nonneural tissues and induce embryo-fetal pathological conditions in critical processes such as neural respiratory control. This review aims at the acute and chronic effects of prenatal exposure to cannabinoids on placental function and the embryo-fetal neurodevelopment of the respiratory pattern. The information provided here will serve as a theoretical framework to critically evaluate the teratogen effects of the consumption of cannabis during pregnancy.
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Affiliation(s)
- Daniela Cáceres
- Laboratorio de Sistemas Neurales, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Martín Ochoa
- Laboratorio de Sistemas Neurales, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Marcelo González-Ortiz
- Laboratorio de Investigación Materno-Fetal (LIMaF), Departamento de Obstetricia y Ginecología, Facultad de Medicina, Universidad de Concepción, Concepción, Chile
| | - Karina Bravo
- Laboratorio de Sistemas Neurales, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
- Facultad de Ingeniería, Universidad Autónoma de Chile, Providencia, Chile
| | - Jaime Eugenín
- Laboratorio de Sistemas Neurales, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile.
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6
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Zhao Y, Pasanen M, Rysä J. Placental ion channels: potential target of chemical exposure. Biol Reprod 2022; 108:41-51. [PMID: 36173899 PMCID: PMC9843680 DOI: 10.1093/biolre/ioac186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 09/23/2022] [Accepted: 09/29/2022] [Indexed: 01/21/2023] Open
Abstract
The placenta is an important organ for the exchange of substances between the fetus and the mother, hormone secretion, and fetoplacental immunological defense. Placenta has an organ-specific distribution of ion channels and trophoblasts, and placental vessels express a large number of ion channels. Several placental housekeeping activities and pregnancy complications are at least partly controlled by ion channels, which are playing an important role in regulating hormone secretion, trophoblastic homeostasis, ion transport, and vasomotor activity. The function of several placental ion channels (Na, Ca, and Cl ion channels, cation channel, nicotinic acetylcholine receptors, and aquaporin-1) is known to be influenced by chemical exposure, i.e., their responses to different chemicals have been tested and confirmed in experimental models. Here, we review the possibility that placental ion channels are targets of toxicological concern in terms of placental function, fetal growth, and development.
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Affiliation(s)
- Yi Zhao
- Department of Obstetrics, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Markku Pasanen
- School of Pharmacy, University of Eastern Finland, Kuopio, Finland
| | - Jaana Rysä
- Correspondence: School of Pharmacy, University of Eastern Finland, POB 1627, Kuopio 70211, Finland. Tel: +358403552412; E-mail:
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7
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Worton SA, Pritchard HAT, Greenwood SL, Alakrawi M, Heazell AEP, Wareing M, Greenstein A, Myers JE. Kynurenine Relaxes Arteries of Normotensive Women and Those With Preeclampsia. Circ Res 2021; 128:1679-1693. [PMID: 33656370 PMCID: PMC8154175 DOI: 10.1161/circresaha.120.317612] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Supplemental Digital Content is available in the text. Rationale: Activation of the kynurenine pathway of tryptophan catabolism by infection and inflammation contributes to the development of systemic hypotension. Commercially-available kynurenine has direct vasorelaxant effects on arteries from several species and reduces systemic blood pressure when administered to normotensive or hypertensive rats. Objectives: To determine whether kynurenine promotes relaxation of human resistance arteries from normotensive and hypertensive pregnant women and to identify the vascular mechanism of its effects. Methods and Results: In isolated omental and myometrial resistance arteries from normotensive pregnant women, kynurenine (1 mmol/L) significantly reduced U46619-induced constriction (omentum N=14, P=2.4×10−3; myometrium N=21–25, P=2.6×10−4) and relaxed preconstricted arteries (N=53, P=1.0×10−11; N=20, P=8.8×10−3). Vasorelaxation persisted following endothelium removal (N=7, P=1.6×10−4) but was completely prevented by inhibition of large-conductance Ca2+-activated K+ channels (BKCa) channels with iberiotoxin (N=9, P=5.7×10−4) or paxilline (N=10, P=2.1×10−17). Accordingly, in isolated vascular smooth muscle cells from omental arteries, kynurenine increased the BKCa current (n=5–8, P=0.022) and the amplitude of spontaneous transient outward currents (n=6, P=0.031) but did not affect spontaneous transient outward current frequency. Kynurenine also increased Ca2+ spark frequency of pressurized omental arteries (n=8, P=0.031). Vasorelaxant effects of kynurenine persisted following inhibition of ryanodine receptors (N=7, P=0.48) but were moderately reduced by inhibition of adenylate cyclase (N=9, P=0.024). In arteries from women with preeclampsia, kynurenine similarly attenuated vasoconstriction (N=15, P=1.3×10−5) and induced BKCa-mediated vasodilation (N=16, P=2.0×10−4). Vasorelaxation in response to kynurenine and a specific BKCa activator, NS11021, was absent in fetal-derived placental resistance arteries in normal pregnancy and preeclampsia. Conclusions: Kynurenine dilates systemic arteries from multiple territories via BKCa activation. Notably, the vasorelaxatory capacity of kynurenine is preserved in preeclampsia, suggesting this approach may have translational potential for the treatment of hypertension in pregnancy. The data warrant further investigation of the potential to exploit this endogenous vasorelaxant as a new treatment for hypertensive pathologies.
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Affiliation(s)
- Stephanie A Worton
- Maternal & Fetal Health Research Centre, Division of Developmental Biology & Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom (S.A.W., S.L.G., A.E.P.H., M.W., J.E.M.).,Manchester University Hospital NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom (S.A.W., A.E.P.H., A.G., J.E.M.)
| | - Harry A T Pritchard
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom (H.A.T.P., M.A., A.G.)
| | - Susan L Greenwood
- Maternal & Fetal Health Research Centre, Division of Developmental Biology & Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom (S.A.W., S.L.G., A.E.P.H., M.W., J.E.M.)
| | - Mariam Alakrawi
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom (H.A.T.P., M.A., A.G.)
| | - Alexander E P Heazell
- Maternal & Fetal Health Research Centre, Division of Developmental Biology & Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom (S.A.W., S.L.G., A.E.P.H., M.W., J.E.M.).,Manchester University Hospital NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom (S.A.W., A.E.P.H., A.G., J.E.M.)
| | - Mark Wareing
- Maternal & Fetal Health Research Centre, Division of Developmental Biology & Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom (S.A.W., S.L.G., A.E.P.H., M.W., J.E.M.)
| | - Adam Greenstein
- Manchester University Hospital NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom (S.A.W., A.E.P.H., A.G., J.E.M.).,Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom (H.A.T.P., M.A., A.G.)
| | - Jenny E Myers
- Maternal & Fetal Health Research Centre, Division of Developmental Biology & Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom (S.A.W., S.L.G., A.E.P.H., M.W., J.E.M.).,Manchester University Hospital NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom (S.A.W., A.E.P.H., A.G., J.E.M.)
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Placental blood flow sensing and regulation in fetal growth restriction. Placenta 2021; 113:23-28. [PMID: 33509641 PMCID: PMC8448138 DOI: 10.1016/j.placenta.2021.01.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/31/2020] [Accepted: 01/08/2021] [Indexed: 12/13/2022]
Abstract
The mechanical force of blood flow is a fundamental determinant of vascular homeostasis. This frictional stimulation of cells, fluid shear stress (FSS), is increasingly recognised as being essential to placental development and function. Here, we focus on the role of FSS in regulating fetoplacental circulatory flow, both in normal pregnancy and that affected by fetal growth restriction (FGR). The fetus is reliant on placental perfusion to meet its circulatory and metabolic demands. Failure of normal vascular adaptation and the mechanisms enabling responsive interaction between fetoplacental and maternal circulations can result in FGR. FSS generates vasodilatation at least partly through the release of endothelial nitric oxide, a process thought to be vital for adequate blood flow. Where FGR is caused by placental dysfunction, placental vascular anatomy is altered, alongside endothelial dysfunction and hypoxia, each impacting upon the complex balance of FSS forces. Identifying specific mechanical sensors and the mechanisms governing how FSS force is converted into biochemical signals is a fast-paced area of research. Here, we raise awareness of Piezo1 proteins, recently discovered to be FSS-sensitive in fetoplacental endothelium, and with emerging roles in NO generation, vascular tone and angiogenesis. We discuss the emerging concept that activating mechanosensors such as Piezo1 ultimately results in the orchestrated processes of placental vascular adaptation. Piecing together the mechanisms governing endothelial responses to FSS in placental insufficiency is an important step towards developing new treatments for FGR.
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Clinical Importance of the Human Umbilical Artery Potassium Channels. Cells 2020; 9:cells9091956. [PMID: 32854241 PMCID: PMC7565333 DOI: 10.3390/cells9091956] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/21/2020] [Accepted: 08/24/2020] [Indexed: 02/06/2023] Open
Abstract
Potassium (K+) channels are usually predominant in the membranes of vascular smooth muscle cells (SMCs). These channels play an important role in regulating the membrane potential and vessel contractility-a role that depends on the vascular bed. Thus, the activity of K+ channels represents one of the main mechanisms regulating the vascular tone in physiological and pathophysiological conditions. Briefly, the activation of K+ channels in SMC leads to hyperpolarization and vasorelaxation, while its inhibition induces depolarization and consequent vascular contraction. Currently, there are four different types of K+ channels described in SMCs: voltage-dependent K+ (KV) channels, calcium-activated K+ (KCa) channels, inward rectifier K+ (Kir) channels, and 2-pore domain K+ (K2P) channels. Due to the fundamental role of K+ channels in excitable cells, these channels are promising therapeutic targets in clinical practice. Therefore, this review discusses the basic properties of the various types of K+ channels, including structure, cellular mechanisms that regulate their activity, and new advances in the development of activators and blockers of these channels. The vascular functions of these channels will be discussed with a focus on vascular SMCs of the human umbilical artery. Then, the clinical importance of K+ channels in the treatment and prevention of cardiovascular diseases during pregnancy, such as gestational hypertension and preeclampsia, will be explored.
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10
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Role of potassium channels in female reproductive system. Obstet Gynecol Sci 2020; 63:565-576. [PMID: 32838485 PMCID: PMC7494774 DOI: 10.5468/ogs.20064] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 06/26/2020] [Indexed: 12/26/2022] Open
Abstract
Potassium channels are widely expressed in most types of cells in living organisms and regulate the functions of a variety of organs, including kidneys, neurons, cardiovascular organs, and pancreas among others. However, the functional roles of potassium channels in the reproductive system is less understood. This mini-review provides information about the localization and functions of potassium channels in the female reproductive system. Five types of potassium channels, which include inward-rectifying (Kir), voltage-gated (Kv), calcium-activated (KCa), 2-pore domain (K2P), and rapidly-gating sodium-activated (Slo) potassium channels are expressed in the hypothalamus, ovaries, and uterus. Their functions include the regulation of hormone release and feedback by Kir6.1 and Kir6.2, which are expressed in the luteal granulosa cells and gonadotropin-releasing hormone neurons respectively, and regulate the functioning of the hypothalamus–pituitary–ovarian axis and the production of progesterone. Both channels are regulated by subtypes of the sulfonylurea receptor (SUR), Kir6.1/SUR2B and Kir6.2/SUR1. Kv and Slo2.1 affect the transition from uterine quiescence in late pregnancy to the state of strong myometrial contractions in labor. Intermediate- and small-conductance KCa modulate the vasodilatation of the placental chorionic plate resistance arteries via the secretion of nitric oxide and endothelium-derived hyperpolarizing factors. Treatment with specific channel activators and inhibitors provides information relevant for clinical use that could help alter the functions of the female reproductive system.
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Sander KN, Ali TY, Warren AY, Hay DP, Broughton Pipkin F, Barrett DA, Khan RN. Pharmacological profile of vascular activity of human stem villous arteries. Placenta 2019; 88:12-19. [PMID: 31574379 DOI: 10.1016/j.placenta.2019.09.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 09/13/2019] [Accepted: 09/16/2019] [Indexed: 11/15/2022]
Abstract
INTRODUCTION The function of the placental vasculature differs considerably from other systemic vascular beds of the human body. A detailed understanding of the normal placental vascular physiology is the foundation to understand perturbed conditions potentially leading to placental dysfunction. METHODS Behaviour of human stem villous arteries isolated from placentae at term pregnancy was assessed using wire myography. Effects of a selection of known vasoconstrictors and vasodilators of the systemic vasculature were assessed. The morphology of stem villous arteries was examined using IHC and TEM. RESULTS Contractile effects in stem villous arteries were caused by U46619, 5-HT, angiotensin II and endothelin-1 (p ≤ 0.05), whereas noradrenaline and AVP failed to result in a contraction. Dilating effects were seen for histamine, riluzole, nifedipine, papaverine, SNP and SQ29548 (p ≤ 0.05) but not for acetylcholine, bradykinin and substance P. DISCUSSION Stem villous arteries behave differently to vessels of the systemic vasculature and results indicate that the placenta is cut off from the systemic maternal vascular regulation. Particularly, endothelium-dependent processes were attenuated in the placental vasculature, creating a need to determine the role of the endothelium in the placenta in future studies.
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Affiliation(s)
- Katrin N Sander
- Division of Medical Science and Graduate Entry Medicine, School of Medicine, University of Nottingham, The Royal Derby Hospital, Uttoxeter Road, Derby, DE22 3DT, UK; Advanced Materials and Healthcare Technologies Division, Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Tayyba Y Ali
- Division of Medical Science and Graduate Entry Medicine, School of Medicine, University of Nottingham, The Royal Derby Hospital, Uttoxeter Road, Derby, DE22 3DT, UK
| | - Averil Y Warren
- Division of Medical Science and Graduate Entry Medicine, School of Medicine, University of Nottingham, The Royal Derby Hospital, Uttoxeter Road, Derby, DE22 3DT, UK
| | - Daniel P Hay
- Division of Medical Science and Graduate Entry Medicine, School of Medicine, University of Nottingham, The Royal Derby Hospital, Uttoxeter Road, Derby, DE22 3DT, UK
| | - Fiona Broughton Pipkin
- Division of Child Health, Obstetrics and Gynaecology, School of Medicine, City Hospital, Maternity Unit, Hucknall Road, Nottingham NG5 1PB, UK
| | - David A Barrett
- Advanced Materials and Healthcare Technologies Division, Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Raheela N Khan
- Division of Medical Science and Graduate Entry Medicine, School of Medicine, University of Nottingham, The Royal Derby Hospital, Uttoxeter Road, Derby, DE22 3DT, UK.
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Abstract
Veins exhibit spontaneous contractile activity, a phenomenon generally termed vasomotion. This is mediated by spontaneous rhythmical contractions of mural cells (i.e. smooth muscle cells (SMCs) or pericytes) in the wall of the vessel. Vasomotion occurs through interconnected oscillators within and between mural cells, entraining their cycles. Pharmacological studies indicate that a key oscillator underlying vasomotion is the rhythmical calcium ion (Ca2+) release-refill cycle of Ca2+ stores. This occurs through opening of inositol 1,4,5-trisphosphate receptor (IP3R)- and/or ryanodine receptor (RyR)-operated Ca2+ release channels in the sarcoplasmic/endoplasmic (SR/ER) reticulum and refilling by the SR/ER reticulum Ca2+ATPase (SERCA). Released Ca2+ from stores near the plasma membrane diffuse through the cytosol to open Ca2+-activated chloride (Cl-) channels, this generating inward current through an efflux of Cl-. The resultant depolarisation leads to the opening of voltage-dependent Ca2+ channels and possibly increased production of IP3, which through Ca2+-induced Ca2+ release (CICR) of IP3Rs and/or RyRs and IP3R-mediated Ca2+ release provide a means by which store oscillators entrain their activity. Intercellular entrainment normally involves current flow through gap junctions that interconnect mural cells and in many cases this is aided by additional connectivity through the endothelium. Once entrainment has occurred the substantial Ca2+ entry that results from the near-synchronous depolarisations leads to rhythmical contractions of the mural cells, this often leading to vessel constriction. The basis for venous/venular vasomotion has yet to be fully delineated but could improve both venous drainage and capillary/venular absorption of blood plasma-associated fluids.
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Abán CE, Accialini PL, Etcheverry T, Leguizamón GF, Martinez NA, Farina MG. Crosstalk Between Nitric Oxide and Endocannabinoid Signaling Pathways in Normal and Pathological Placentation. Front Physiol 2018; 9:1699. [PMID: 30564135 PMCID: PMC6288445 DOI: 10.3389/fphys.2018.01699] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 11/12/2018] [Indexed: 12/16/2022] Open
Abstract
Endocannabinoids are a group of endogenous lipid mediators that act as ligands of cannabinoid and vanilloid receptors, activating multiple signal transduction pathways. Together with enzymes responsible for their synthesis and degradation, these compounds constitute the endocannabinoid system (ECS), which is involved in different physiological processes in reproduction. The placenta, which is essential for the success of gestation and optimal fetal growth, undergoes constant tissue remodeling. ECS members are expressed in trophoblast cells, and current evidence suggests that this system is involved in placental development, apoptosis, and syncytialization. Impairment of endocannabinoid signaling has been associated with several pathological conditions such as intrauterine growth restriction and preeclampsia. Both clinical entities are characterized by dysregulation on vascular perfusion where nitrergic system performs a pivotal role. Nitric oxide (NO) is a potent local vasodepressor that exerts a critical role in the regulation of hemodynamic flow, contributing to the maintenance of low vascular resistance in the feto-placental circulation. NO production could be affected by different factors and growing evidence suggests that the endocannabinoid mediators may regulate nitrergic signaling. Herein, we review emerging knowledge supporting ECS-mediated regulation of NO production in normal placentation. Finally, we discuss how alterations in these systems could affect homoeostasis and contribute to the occurrence of placental-mediated pregnancy complications. Given the impact on women and perinatal heath, we will focus on current knowledge regarding the effects of ECS on nitrergic system in normal and pathological placentation.
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Affiliation(s)
- Cyntia E Abán
- Laboratorio de Investigación Aplicada a las Neurociencias (LIAN), FLENI - CONICET, Belén de Escobar, Argentina
| | - Paula L Accialini
- Laboratorio de Fisiopatología Placentaria, CEFyBO-UBA-CONICET, Buenos Aires, Argentina
| | - Tomás Etcheverry
- Laboratorio de Fisiopatología Placentaria, CEFyBO-UBA-CONICET, Buenos Aires, Argentina
| | | | - Nora A Martinez
- Laboratorio de Biología de la Reproducción, IFIBIO-UBA-CONICET, Buenos Aires, Argentina.,Red Iberoamericana de Alteraciones Vasculares Asociadas a Trastornos del Embarazo (RIVA-TREM), Buenos Aires, Argentina
| | - Mariana G Farina
- Laboratorio de Fisiopatología Placentaria, CEFyBO-UBA-CONICET, Buenos Aires, Argentina.,Red Iberoamericana de Alteraciones Vasculares Asociadas a Trastornos del Embarazo (RIVA-TREM), Buenos Aires, Argentina
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Cabrera L, Saavedra A, Rojas S, Cid M, Valenzuela C, Gallegos D, Careaga P, Basualto E, Haensgen A, Peña E, Rivas C, Vera JC, Gallardo V, Zúñiga L, Escudero C, Sobrevia L, Wareing M, González M. Insulin Induces Relaxation and Decreases Hydrogen Peroxide-Induced Vasoconstriction in Human Placental Vascular Bed in a Mechanism Mediated by Calcium-Activated Potassium Channels and L-Arginine/Nitric Oxide Pathways. Front Physiol 2016; 7:529. [PMID: 27920724 PMCID: PMC5118463 DOI: 10.3389/fphys.2016.00529] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 10/25/2016] [Indexed: 01/04/2023] Open
Abstract
HIGHLIGHTSShort-term incubation with insulin increases the L-arginine transport in HUVECs. Short-term incubation with insulin increases the NO synthesis in HUVECs. Insulin induces relaxation in human placental vascular bed. Insulin attenuates the constriction induced by hydrogen peroxide in human placenta. The relaxation induced by insulin is dependent on BKCa channels activity in human placenta.
Insulin induces relaxation in umbilical veins, increasing the expression of human amino acid transporter 1 (hCAT-1) and nitric oxide synthesis (NO) in human umbilical vein endothelial cells (HUVECs). Short-term effects of insulin on vasculature have been reported in healthy subjects and cell cultures; however, its mechanisms remain unknown. The aim of this study was to characterize the effect of acute incubation with insulin on the regulation of vascular tone of placental vasculature. HUVECs and chorionic vein rings were isolated from normal pregnancies. The effect of insulin on NO synthesis, L-arginine transport, and hCAT-1 abundance was measured in HUVECs. Isometric tension induced by U46619 (thromboxane A2 analog) or hydrogen peroxide (H2O2) were measured in vessels previously incubated 30 min with insulin and/or the following pharmacological inhibitors: tetraethylammonium (KCa channels), iberiotoxin (BKCa channels), genistein (tyrosine kinases), and wortmannin (phosphatidylinositol 3-kinase). Insulin increases L-arginine transport and NO synthesis in HUVECs. In the placenta, this hormone caused relaxation of the chorionic vein, and reduced perfusion pressure in placental cotyledons. In vessels pre-incubated with insulin, the constriction evoked by H2O2 and U46619 was attenuated and the effect on H2O2-induced constriction was blocked with tetraethylammonium and iberiotoxin, but not with genistein, or wortmannin. Insulin rapidly dilates the placental vasculature through a mechanism involving activity of BKCa channels and L-arginine/NO pathway in endothelial cells. This phenomenon is related to quick increases of hCAT-1 abundance and higher capacity of endothelial cells to take up L-arginine and generate NO.
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Affiliation(s)
- Lissette Cabrera
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de ConcepciónConcepción, Chile; Department of Morphophysiology, Faculty of Medicine, Universidad Diego PortalesSantiago, Chile
| | - Andrea Saavedra
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Susana Rojas
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Marcela Cid
- Department of Obstetrics and Childcare, Faculty of Medicine, Universidad de Concepción Concepción, Chile
| | - Cristina Valenzuela
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - David Gallegos
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Pamela Careaga
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Emerita Basualto
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Astrid Haensgen
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Eduardo Peña
- Department of Pathophysiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Coralia Rivas
- Department of Pathophysiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Juan Carlos Vera
- Department of Pathophysiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Victoria Gallardo
- Department of Pathophysiology, Faculty of Biological Sciences, Universidad de ConcepciónConcepción, Chile; Group of Research and Innovation in Vascular Health (GRIVAS Health)Chillán, Chile
| | - Leandro Zúñiga
- Centro de Investigaciones Médicas (CIM), School of Medicine, Universidad de Talca Talca, Chile
| | - Carlos Escudero
- Group of Research and Innovation in Vascular Health (GRIVAS Health)Chillán, Chile; Vascular Physiology Laboratory, Group of Investigation in Tumor Angiogenesis (GIANT), Department of Basic Sciences, Universidad del BiobíoChillán, Chile
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de ChileSantiago, Chile; Department of Physiology, Faculty of Pharmacy, Universidad de SevillaSeville, Spain; University of Queensland Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of QueenslandHerston, QLD, Australia
| | - Mark Wareing
- Maternal and Fetal Health Research Centre, Institute of Human Development, University of ManchesterManchester, UK; Maternal and Fetal Health Research Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science CentreManchester, UK
| | - Marcelo González
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de ConcepciónConcepción, Chile; Group of Research and Innovation in Vascular Health (GRIVAS Health)Chillán, Chile
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Lee JH, Park JW, Byun JK, Kim HK, Ryu PD, Lee SY, Kim DY. Silencing of voltage-gated potassium channel KV9.3 inhibits proliferation in human colon and lung carcinoma cells. Oncotarget 2016; 6:8132-43. [PMID: 25924237 PMCID: PMC4480740 DOI: 10.18632/oncotarget.3517] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 02/03/2015] [Indexed: 01/12/2023] Open
Abstract
Voltage-gated potassium (Kv) channels are known to be involved in cancer development and cancer cell proliferation. KV9.3, an electronically silent subunit, forms heterotetramers with KV2.1 in excitable cells and modulates its electrophysiological properties. However, the role of KV9.3 alone in non-excitable cancer cells has not been studied. Here, we evaluated the effect of silencing KV9.3 on cancer cell proliferation in HCT15 colon carcinoma cells and A549 lung adenocarcinoma cells. We confirmed the expression of KV9.3 mRNA in HCT15 and A549 cells and showed that silencing KV9.3 using small interfering RNA caused G0/G1 cell cycle arrest and alterations in cell cycle regulatory proteins in both HCT15 and A549 cells without affecting apoptosis. Also, stable knockdown of KV9.3 expression using short-hairpin RNA inhibited tumor growth in SCID mouse xenograft model. Using a bioinformatics approach, we identified Sp1 binding sites in the promoter region of the gene encoding KV9.3. We further found that Sp1 bound to this region and showed that the Sp1 inhibitor, mithramycin A, induced a concentration-dependent decrease in KV9.3 expression. Taken together, these data suggest that knockdown of KV9.3 inhibits proliferation in colon carcinoma and lung adenocarcinoma cell lines and may be regulated by Sp1.
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Affiliation(s)
- Jeong-Ha Lee
- Laboratory of Veterinary Pathology, Seoul National University, Seoul, Korea
| | - Jun-Won Park
- Biomolecular Function Research Branch, National Cancer Center, Goyang, Gyeonggi, Korea
| | - Jun Kyu Byun
- Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - Hark Kyun Kim
- Biomolecular Function Research Branch, National Cancer Center, Goyang, Gyeonggi, Korea
| | - Pan Dong Ryu
- Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - So Yeong Lee
- Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - Dae-Yong Kim
- Laboratory of Veterinary Pathology, Seoul National University, Seoul, Korea
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16
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Bocksteins E. Kv5, Kv6, Kv8, and Kv9 subunits: No simple silent bystanders. J Gen Physiol 2016; 147:105-25. [PMID: 26755771 PMCID: PMC4727947 DOI: 10.1085/jgp.201511507] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 12/11/2015] [Indexed: 12/19/2022] Open
Abstract
Members of the electrically silent voltage-gated K(+) (Kv) subfamilies (Kv5, Kv6, Kv8, and Kv9, collectively identified as electrically silent voltage-gated K(+) channel [KvS] subunits) do not form functional homotetrameric channels but assemble with Kv2 subunits into heterotetrameric Kv2/KvS channels with unique biophysical properties. Unlike the ubiquitously expressed Kv2 subunits, KvS subunits show a more restricted expression. This raises the possibility that Kv2/KvS heterotetramers have tissue-specific functions, making them potential targets for the development of novel therapeutic strategies. Here, I provide an overview of the expression of KvS subunits in different tissues and discuss their proposed role in various physiological and pathophysiological processes. This overview demonstrates the importance of KvS subunits and Kv2/KvS heterotetramers in vivo and the importance of considering KvS subunits and Kv2/KvS heterotetramers in the development of novel treatments.
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Affiliation(s)
- Elke Bocksteins
- Laboratory for Molecular Biophysics, Physiology, and Pharmacology, Department for Biomedical Sciences, University of Antwerp, 2610 Antwerp, Belgium
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17
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Su EJ. Role of the fetoplacental endothelium in fetal growth restriction with abnormal umbilical artery Doppler velocimetry. Am J Obstet Gynecol 2015; 213:S123-30. [PMID: 26428491 DOI: 10.1016/j.ajog.2015.06.038] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 06/12/2015] [Accepted: 06/16/2015] [Indexed: 01/30/2023]
Abstract
Growth-restricted fetuses with absent or reversed end-diastolic velocities in the umbilical artery are at substantially increased risk for adverse perinatal and long-term outcome, even in comparison to growth-restricted fetuses with preserved end-diastolic velocities. Translational studies show that this Doppler velocimetry correlates with fetoplacental blood flow, with absent or reversed end-diastolic velocities signifying abnormally elevated resistance within the placental vasculature. The fetoplacental vasculature is unique in that it is not subject to autonomic regulation, unlike other vascular beds. Instead, humoral mediators, many of which are synthesized by local endothelial cells, regulate placental vascular resistance. Existing data demonstrate that in growth-restricted pregnancies complicated by absent or reversed umbilical artery end-diastolic velocities, an imbalance in production of these vasoactive substances occurs, favoring vasoconstriction. Morphologically, placentas from these pregnancies also demonstrate impaired angiogenesis, whereby vessels within the terminal villi are sparsely branched, abnormally thin, and elongated. This structural deviation from normal placental angiogenesis restricts blood flow and further contributes to elevated fetoplacental vascular resistance. Although considerable work has been done in the field of fetoplacental vascular development and function, much remains unknown about the mechanisms underlying impaired development and function of the human fetoplacental vasculature, especially in the context of severe fetal growth restriction with absent or reversed umbilical artery end-diastolic velocities. Fetoplacental endothelial cells are key regulators of angiogenesis and vasomotor tone. A thorough understanding of their role in placental vascular biology carries the significant potential of discovering clinically relevant and innovative approaches to prevention and treatment of fetal growth restriction with compromised umbilical artery end-diastolic velocities.
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Mills TA, Greenwood SL, Devlin G, Shweikh Y, Robinson M, Cowley E, Hayward CE, Cottrell EC, Tropea T, Brereton MF, Dalby-Brown W, Wareing M. Activation of KV7 channels stimulates vasodilatation of human placental chorionic plate arteries. Placenta 2015; 36:638-44. [PMID: 25862611 DOI: 10.1016/j.placenta.2015.03.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 03/12/2015] [Accepted: 03/14/2015] [Indexed: 02/01/2023]
Abstract
INTRODUCTION Potassium (K(+)) channels are key regulators of vascular smooth muscle cell (VSMC) excitability. In systemic small arteries, Kv7 channel expression/activity has been noted and a role in vascular tone regulation demonstrated. We aimed to demonstrate functional Kv7 channels in human fetoplacental small arteries. METHODS Human placental chorionic plate arteries (CPAs) were obtained at term. CPA responses to Kv7 channel modulators was determined by wire myography. Presence of Kv7 channel mRNA (encoded by KCNQ1-5) and protein expression were assessed by RT-PCR and immunohistochemistry/immunofluorescence, respectively. RESULTS Kv7 channel blockade with linopirdine increased CPA basal tone and AVP-induced contraction. Pre-contracted CPAs (AVP; 80 mM K(+) depolarization solution) exhibited significant relaxation to flupirtine, retigabine, the acrylamide (S)-1, and (S) BMS-204352, differential activators of Kv7.1 - Kv7.5 channels. All CPAs assessed expressed KCNQ1 and KCNQ3-5 mRNA; KCNQ2 was expressed only in a subset of CPAs. Kv7 protein expression was confirmed in intact CPAs and isolated VSMCs. DISCUSSION Kv7 channels are present and active in fetoplacental vessels, contributing to vascular tone regulation in normal pregnancy. Targeting these channels may represent a therapeutic intervention in pregnancies complicated by increased vascular resistance.
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Affiliation(s)
- T A Mills
- School of Nursing, Midwifery and Social Work, The University of Manchester, Jean McFarlane Building, Oxford Road, Manchester M13 9PL, United Kingdom.
| | - S L Greenwood
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom.
| | - G Devlin
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom.
| | - Y Shweikh
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom
| | - M Robinson
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom
| | - E Cowley
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom.
| | - C E Hayward
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom.
| | - E C Cottrell
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom.
| | - T Tropea
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom; Department of Biology, Ecology and Earth Sciences, University of Calabria, Arcavacata di Rende, CS, Italy.
| | - M F Brereton
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom.
| | - W Dalby-Brown
- Pcovery Aps, Thorvaldsensvej 57, DK-1871 Frederiksberg C, Denmark.
| | - M Wareing
- Maternal and Fetal Health Research Centre, Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom.
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Renigunta V, Schlichthörl G, Daut J. Much more than a leak: structure and function of K₂p-channels. Pflugers Arch 2015; 467:867-94. [PMID: 25791628 DOI: 10.1007/s00424-015-1703-7] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 03/09/2015] [Indexed: 11/27/2022]
Abstract
Over the last decade, we have seen an enormous increase in the number of experimental studies on two-pore-domain potassium channels (K2P-channels). The collection of reviews and original articles compiled for this special issue of Pflügers Archiv aims to give an up-to-date summary of what is known about the physiology and pathophysiology of K2P-channels. This introductory overview briefly describes the structure of K2P-channels and their function in different organs. Its main aim is to provide some background information for the 19 reviews and original articles of this special issue of Pflügers Archiv. It is not intended to be a comprehensive review; instead, this introductory overview focuses on some unresolved questions and controversial issues, such as: Do K2P-channels display voltage-dependent gating? Do K2P-channels contribute to the generation of action potentials? What is the functional role of alternative translation initiation? Do K2P-channels have one or two or more gates? We come to the conclusion that we are just beginning to understand the extremely complex regulation of these fascinating channels, which are often inadequately described as 'leak channels'.
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Affiliation(s)
- Vijay Renigunta
- Institute of Physiology and Pathophysiology, Marburg University, 35037, Marburg, Germany
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20
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Protić D, Radunović N, Spremović-Rađenović S, Živanović V, Heinle H, Petrović A, Gojković-Bukarica L. The Role of Potassium Channels in the Vasodilatation Induced by Resveratrol and Naringenin in Isolated Human Umbilical Vein. Drug Dev Res 2015; 76:17-23. [PMID: 25619904 DOI: 10.1002/ddr.21236] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 12/01/2014] [Indexed: 01/18/2023]
Abstract
Preclinical Research Potassium (K+ ) channels have a key role in the maintenance of smooth muscle tone; a variety of agonists can modify the tone by altering K+ -channel activity. The aim of this study was assess the effects of the phenols, resveratrol, and naringenin on K+ -channels of the vascular smooth muscle. Segments of human umbilical vein (HUV) without endothelium were precontracted using serotonin (100 μM) or 100 mM K+ to derive cumulative concentration-response curves using increasing concentrations of resveratrol or naringenin. K+ -channel inhibitors were added in the bath before resveratrol (1-100 μM) or naringenin (0.01-1 mM) in assess the role of K+ -channels in their effects on HUV precontracted by serotonin. 4-Aminopiridine (4-AP; 1 mM), a nonselective blocker of voltage-dependent, tetraethylammonium (TEA; 1 mM) and barium chloride (1 mM), a nonselective blocker of Ca2+ -dependent and inward rectifier K+ -channels (respectively) induced significant shifts to the right (P < 0.05) of resveratrol. concentration-response curves. The effect of naringenin was antagonized by 4-AP (1 mM). 4-AP-, TEA-, and barium chloride-sensitive K+ -channels are probably involved in the resveratrol vasodilatatory effect, while naringenin seems to affect 4-AP-sensitive K+ -channels. However, other mechanisms of vasodilation induced by polyphenols could not be excluded. Drug Dev Res, 2015. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Dragana Protić
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
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Ali TY, Broughton Pipkin F, Khan RN. The effect of pH and ion channel modulators on human placental arteries. PLoS One 2014; 9:e114405. [PMID: 25490401 PMCID: PMC4260857 DOI: 10.1371/journal.pone.0114405] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Accepted: 11/06/2014] [Indexed: 12/31/2022] Open
Abstract
Chorionic plate arteries (CPA) are located at the maternofetal interface where they are able to respond to local metabolic changes. Unlike many other types of vasculature, the placenta lacks nervous control and requires autoregulation for controlling blood flow. The placental circulation, which is of low-resistance, may become hypoxic easily leading to fetal acidosis and fetal distress however the role of the ion channels in these circumstances is not well-understood. Active potassium channel conductances that are subject to local physicochemical modulation may serve as pathways through which such signals are transduced. The aim of this study was to investigate the modulation of CPA by pH and the channels implicated in these responses using wire myography. CPA were isolated from healthy placentae and pre-contracted with U46619 before testing the effects of extracellular pH using 1 M lactic acid over the pH range 7.4 - 6.4 in the presence of a variety of ion channel modulators. A change from pH 7.4 to 7.2 produced a 29±3% (n = 9) relaxation of CPA which increased to 61±4% at the lowest pH of 6.4. In vessels isolated from placentae of women with pre-eclampsia (n = 6), pH responses were attenuated. L-methionine increased the relaxation to 67±7% (n = 6; p<0.001) at pH 6.4. Similarly the TASK 1/3 blocker zinc chloride (1 mM) gave a maximum relaxation of 72±5% (n = 8; p<0.01) which compared with the relaxation produced by the TREK-1 opener riluzole (75±5%; n = 6). Several other modulators induced no significant changes in vascular responses. Our study confirmed expression of several ion channel subtypes in CPA with our results indicating that extracellular pH within the physiological range has an important role in controlling vasodilatation in the human term placenta.
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Affiliation(s)
- Tayyba Y Ali
- Division of Medical Sciences & Graduate Entry Medicine, School of Medicine, University of Nottingham, Royal Derby Hospital Centre, Uttoxeter Road, Derby DE22 3DT, United Kingdom
| | - Fiona Broughton Pipkin
- Division of Medical Sciences & Graduate Entry Medicine, School of Medicine, University of Nottingham, Royal Derby Hospital Centre, Uttoxeter Road, Derby DE22 3DT, United Kingdom
| | - Raheela N Khan
- Division of Medical Sciences & Graduate Entry Medicine, School of Medicine, University of Nottingham, Royal Derby Hospital Centre, Uttoxeter Road, Derby DE22 3DT, United Kingdom
- * E-mail:
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Rodríguez I, González M. Physiological mechanisms of vascular response induced by shear stress and effect of exercise in systemic and placental circulation. Front Pharmacol 2014; 5:209. [PMID: 25278895 PMCID: PMC4165280 DOI: 10.3389/fphar.2014.00209] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Accepted: 08/26/2014] [Indexed: 12/19/2022] Open
Abstract
Physiological vascular function regulation is essential for cardiovascular health and depends on adequate control of molecular mechanisms triggered by endothelial cells in response to mechanical and chemical stimuli induced by blood flow. Endothelial dysfunction is one of the main risk factors of cardiovascular pathology, where the imbalance between the synthesis of vasodilator and vasoconstrictor molecules is common in the development of vascular disorders in systemic and placental circulation. In the placenta, an organ without autonomic innervations, the local control of vascular tone is critical for maintenance of fetal growth and mechanisms that underlie shear stress response induced by blood flow are essential during pregnancy. In this field, shear stress induced by moderate exercise is one of the most important mechanisms to improve vascular function through nitric oxide synthesis and stimulation of mechanical response of endothelial cells triggered by ion channels, caveolae, endothelial NO synthase, and vascular endothelial growth factor, among others. The demand for oxygen and nutrients by tissues and organs, especially in placentation and pregnancy, determines blood flow parameters, and physiological adaptations of vascular beds for covering metabolic requirements. In this regard, moderate exercise versus sedentarism shows potential benefits for improving vascular function associated with the enhancement of molecular mechanisms induced by shear stress. In this review, we collect evidence about molecular bases of physiological response to shear stress in order to highlight the relevance of moderate exercise-training for vascular health in adult and fetal life.
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Affiliation(s)
- Iván Rodríguez
- Faculty of Health Science, Universidad San Sebastián Concepción, Chile ; PhD Program in Medical Sciences, Faculty of Medicine, Universidad de La Frontera Temuco, Chile
| | - Marcelo González
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile ; Group of Research and Innovation in Vascular Health Chillán, Chile
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23
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Wareing M. Oxygen sensitivity, potassium channels, and regulation of placental vascular tone. Microcirculation 2014; 21:58-66. [PMID: 23710683 DOI: 10.1111/micc.12069] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 05/21/2013] [Indexed: 12/17/2022]
Abstract
The human fetoplacental vasculature is a low-resistance circulation with deoxygenated arterial relative to venous blood. The placenta lacks neuronal innervation suggesting that local physical (e.g., oxygenation; flow rate), paracrine (e.g., endothelial cell nitric oxide), and circulating (e.g., angiotensin II) factors will contribute to blood flow regulation in small fetoplacental vessels. Oxygenation (specifically hypoxia) has received particular attention. At the macro-level, hypoxic challenge increases vascular resistance, but the data's physiological relevance remains questionable. K(+) channels are a diverse family of proteins known to play important roles in the normal physiological functions of endothelial and smooth muscle cells of a variety of vascular beds. K(+) channels are categorized by their predicted transmembrane structure or gating properties. A small number of perfused placental cotyledon and isolated blood vessels studies have assessed K(+) channel activity. Specific activator/inhibitor application suggests functional voltage-gated channels, whereas toxin inhibitor studies have documented KCa channel activity. Pharmacological KATP channel activation significantly dilates preconstricted placental arteries and veins. There is a paucity of cell subtype-specific expression studies of placental K(+) channels. This review focuses on the roles of K(+) channels and oxygenation in controlling reactivity of small fetoplacental blood vessels.
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Affiliation(s)
- Mark Wareing
- Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, Manchester, UK; Maternal and Fetal Health Research Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
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24
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Martín P, Rebolledo A, Palomo ARR, Moncada M, Piccinini L, Milesi V. Diversity of potassium channels in human umbilical artery smooth muscle cells: a review of their roles in human umbilical artery contraction. Reprod Sci 2014; 21:432-41. [PMID: 24084522 PMCID: PMC3960844 DOI: 10.1177/1933719113504468] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Through their control of cell membrane potential, potassium (K(+)) channels are among the best known regulators of vascular tone. This article discusses the expression and function of K(+) channels in human umbilical artery smooth muscle cells (HUASMCs). We review the bibliographic reports and also present single-channel data recorded in freshly isolated cells. Electrophysiological properties of big conductance, voltage- and Ca(2+)-sensitive K(+) channel and voltage-dependent K(+) channels are clearly established in this vessel, where they are involved in contractile state regulation. Their role in the maintenance of membrane potential is an important control mechanism in the determination of the vessel diameter. Additionally, small conductance Ca(2+)-sensitive K(+) channels, 2-pore domains K(+) channels and inward rectifier K(+) channels also appear to be present in HUASMCs, while intermediate conductance Ca(2+)-sensitive K(+) channels and ATP-sensitive K(+) channels could not be identified. In both cases, additional investigation is necessary to reach conclusive evidence of their expression and/or functional role in HUASMCs. Finally, we discuss the role of K(+) channels in pregnancy-related pathologies like gestational diabetes and preeclampsia.
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Affiliation(s)
- Pedro Martín
- Facultad de Ciencias Exactas, GINFIV—Grupo de Investigación en Fisiología Vascular, Universidad Nacional de La Plata, La Plata, Argentina
| | - Alejandro Rebolledo
- Facultad de Ciencias Exactas, GINFIV—Grupo de Investigación en Fisiología Vascular, Universidad Nacional de La Plata, La Plata, Argentina
| | - Ana Rocio Roldán Palomo
- Facultad de Ciencias Exactas, GINFIV—Grupo de Investigación en Fisiología Vascular, Universidad Nacional de La Plata, La Plata, Argentina
| | - Melisa Moncada
- Facultad de Ciencias Exactas, GINFIV—Grupo de Investigación en Fisiología Vascular, Universidad Nacional de La Plata, La Plata, Argentina
| | - Luciano Piccinini
- Facultad de Ciencias Exactas, GINFIV—Grupo de Investigación en Fisiología Vascular, Universidad Nacional de La Plata, La Plata, Argentina
| | - Verónica Milesi
- Facultad de Ciencias Exactas, GINFIV—Grupo de Investigación en Fisiología Vascular, Universidad Nacional de La Plata, La Plata, Argentina
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25
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Protić D, Beleslin-Čokić B, Spremović-Rađenović S, Radunović N, Heinle H, Šćepanović R, Gojković Bukarica L. The Different Effects of Resveratrol and Naringenin on Isolated Human Umbilical Vein: The Role of ATP-Sensitive K+
Channels. Phytother Res 2014; 28:1412-8. [DOI: 10.1002/ptr.5145] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 02/19/2014] [Accepted: 02/21/2014] [Indexed: 01/06/2023]
Affiliation(s)
- Dragana Protić
- Department of Pharmacology; Clinical Pharmacology and Toxicology; Faculty of Medicine; University of Belgrade; 11000 Belgrade Serbia
| | - Bojana Beleslin-Čokić
- Clinic for Endocrinology, Diabetes and Metabolic Diseases, Clinical Center of Serbia; Dr. Subotica 13 11000 Belgrade Serbia
| | - Svetlana Spremović-Rađenović
- Faculty of Medicine; University of Belgrade, Clinic for Gynecology and Obstetrics, Clinical Center of Serbia; 11000 Belgrade Serbia
| | - Nebojša Radunović
- Faculty of Medicine; University of Belgrade, Clinic for Gynecology and Obstetrics, Clinical Center of Serbia; 11000 Belgrade Serbia
| | - Helmut Heinle
- Institute of Physiology; University of Tüebingen; Germany
| | - Radisav Šćepanović
- Faculty of Medicine; University of Belgrade, Clinical Center Dr. Dragisa Misovic; 11000 Belgrade Serbia
| | - Ljiljana Gojković Bukarica
- Department of Pharmacology; Clinical Pharmacology and Toxicology; Faculty of Medicine; University of Belgrade; 11000 Belgrade Serbia
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26
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Frolov RV, Singh S. Celecoxib and ion channels: a story of unexpected discoveries. Eur J Pharmacol 2014; 730:61-71. [PMID: 24630832 DOI: 10.1016/j.ejphar.2014.02.032] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 01/28/2014] [Accepted: 02/18/2014] [Indexed: 10/25/2022]
Abstract
Celecoxib (Celebrex), a highly popular selective inhibitor of cyclooxygenase-2, can modulate ion channels and alter functioning of neurons and myocytes at clinically relevant concentrations independently of cyclooxygenase inhibition. In experimental systems varying from Drosophila to primary mammalian and human cell lines, celecoxib inhibits many voltage-activated Na(+), Ca(2+), and K(+) channels, including NaV1.5, L- and T-type Ca(2+) channels, KV1.5, KV2.1, KV4.3, KV7.1, KV11.1 (hERG), while stimulating other K(+) channels-KV7.2-5 and, possibly, KV11.1 (hERG) channels under certain conditions. In this review, we summarize the information currently available on the effects of celecoxib on ion channels, examine mechanistic aspects of drug action and the concomitant changes at the cellular and organ levels, and discuss these findings in the therapeutic context.
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Affiliation(s)
- Roman V Frolov
- Department of Physical Sciences, Division of Biophysics, University of Oulu, PO Box 3000, 90014 Oulun Yliopisto, Finland.
| | - Satpal Singh
- Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, NY 14214, USA
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27
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Mistry HD, Kurlak LO, Whitley GS, Cartwright JE, Broughton Pipkin F, Tribe RM. Expression of voltage-dependent potassium channels in first trimester human placentae. Placenta 2014; 35:337-40. [PMID: 24646441 DOI: 10.1016/j.placenta.2014.02.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 02/18/2014] [Accepted: 02/20/2014] [Indexed: 11/24/2022]
Abstract
Potassium channel α-subunits encoded by KCNQ1-5 genes form voltage-dependent channels (KV7), modulated by KCNE1-5 encoded accessory proteins. The aim was to determine KCNQ and KCNE mRNA expression and assess protein expression/localisation of the KCNQ3 and KCNE5 isoforms in first trimester placental tissue. Placentae were obtained from women undergoing elective surgical termination of pregnancy (TOP) at ≤ 10 weeks' (early TOP) and >10 weeks' (mid TOP) gestations. KCNQ1-5 expression was unchanged during the first trimester. KCNE5 expression increased in mid TOP vs. early TOP samples (P = 0.022). This novel study reports mRNA and protein expression of KV7 channels in first trimester placentae.
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Affiliation(s)
- H D Mistry
- Division of Women's Health, King's College London, Women's Health Academic Centre, KHP, St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, UK; Department of Nephrology, Hypertension, Clinical Pharmacology and of Clinical Research, University of Bern, Berne CH-3010, Switzerland.
| | - L O Kurlak
- Department of Obstetrics & Gynaecology, School of Medicine, University of Nottingham, Nottingham NG5 1PB, UK
| | - G S Whitley
- Division of Biomedical Sciences, St George's University of London, London SW17 0RE, UK
| | - J E Cartwright
- Division of Biomedical Sciences, St George's University of London, London SW17 0RE, UK
| | - F Broughton Pipkin
- Department of Obstetrics & Gynaecology, School of Medicine, University of Nottingham, Nottingham NG5 1PB, UK
| | - R M Tribe
- Division of Women's Health, King's College London, Women's Health Academic Centre, KHP, St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, UK
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28
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Frolov RV, Bagati A, Casino B, Singh S. Potassium channels in Drosophila: historical breakthroughs, significance, and perspectives. J Neurogenet 2013. [PMID: 23181728 DOI: 10.3109/01677063.2012.744990] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Drosophila has enabled important breakthroughs in K(+) channel research, including identification and fi rst cloning of a voltage-activated K(+) channel, Shaker, a founding member of the K(V)1 family. Drosophila has also helped in discovering other K(+) channels, such as Shab, Shaw, Shal, Eag, Sei, Elk, and also Slo, a Ca(2+) - and voltage-dependent K(+) channel. These findings have contributed significantly to our understanding of ion channels and their role in physiology. Drosophila continues to play an important role in ion channel studies, benefiting from an unparalleled arsenal of genetic tools and availability of tens of thousands of genetically modified strains. These tools allow deletion, expression, or misexpression of almost any gene in question with temporal and spatial control. The combination of these tools and resources with the use of forward genetic approach in Drosophila further enhances its strength as a model system. There are many areas in which Drosophila can further help our understanding of ion channels and their function. These include signaling pathways involved in regulating and modulating ion channels, basic information on channels and currents where very little is currently known, and the role of ion channels in physiology and pathology.
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Affiliation(s)
- Roman V Frolov
- Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, New York 14214-3000, USA
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29
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Brereton MF, Wareing M, Jones RL, Greenwood SL. Characterisation of K+ channels in human fetoplacental vascular smooth muscle cells. PLoS One 2013; 8:e57451. [PMID: 23437391 PMCID: PMC3578819 DOI: 10.1371/journal.pone.0057451] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 01/24/2013] [Indexed: 11/18/2022] Open
Abstract
Adequate blood flow through placental chorionic plate resistance arteries (CPAs) is necessary for oxygen and nutrient transfer to the fetus and a successful pregnancy. In non-placental vascular smooth muscle cells (SMCs), K(+) channels regulate contraction, vascular tone and blood flow. Previous studies showed that K(+) channel modulators alter CPA tone, but did not distinguish between effects on K(+) channels in endothelial cells and SMCs. In this study, we developed a preparation of freshly isolated CPASMCs of normal pregnancy and investigated K(+) channel expression and function. CPASMCs were isolated from normal human term placentas using enzymatic digestion. Purity and phenotype was confirmed with immunocytochemistry. Whole-cell patch clamp was used to assess K(+) channel currents, and mRNA and protein expression was determined in intact CPAs and isolated SMCs with RT-PCR and immunostaining. Isolated SMCs expressed α-actin but not CD31, a marker of endothelial cells. CPASMCs and intact CPAs expressed h-caldesmon and non-muscle myosin heavy chain-2; phenotypic markers of contractile and synthetic SMCs respectively. Whole-cell currents were inhibited by 4-AP, TEA, charybdotoxin and iberiotoxin implicating functional K(v) and BK(Ca) channels. 1-EBIO enhanced whole cell currents which were abolished by TRAM-34 and reduced by apamin indicating activation of IK(Ca) and SK(Ca) respectively. BK(Ca), IK(Ca) and SK(Ca)3 mRNA and/or protein were expressed in CPASMCs and intact CPAs. This study provides the first direct evidence for functional K(v), BK(Ca,) IK(Ca) and SK(Ca) channels in CPASMCs. These cells display a mixed phenotype implicating a dual role for CPASMCs in controlling both fetoplacental vascular resistance and vasculogenesis.
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MESH Headings
- Actins/genetics
- Actins/metabolism
- Calcium/metabolism
- Calmodulin-Binding Proteins/genetics
- Calmodulin-Binding Proteins/metabolism
- Chorion/blood supply
- Chorion/cytology
- Chorion/drug effects
- Chorion/metabolism
- Female
- Fetus
- Gene Expression/drug effects
- Humans
- Membrane Potentials/drug effects
- Membrane Potentials/physiology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/cytology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Myosin Heavy Chains/genetics
- Myosin Heavy Chains/metabolism
- Patch-Clamp Techniques
- Placenta/blood supply
- Placenta/cytology
- Placenta/drug effects
- Placenta/metabolism
- Potassium/metabolism
- Potassium Channel Blockers/pharmacology
- Potassium Channels, Calcium-Activated/antagonists & inhibitors
- Potassium Channels, Calcium-Activated/classification
- Potassium Channels, Calcium-Activated/genetics
- Potassium Channels, Calcium-Activated/metabolism
- Potassium Channels, Voltage-Gated/antagonists & inhibitors
- Potassium Channels, Voltage-Gated/classification
- Potassium Channels, Voltage-Gated/genetics
- Potassium Channels, Voltage-Gated/metabolism
- Pregnancy
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Affiliation(s)
- Melissa F Brereton
- Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, St. Mary's Hospital, Manchester, United Kingdom.
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Fyfe GK, Panicker S, Jones RL, Wareing M. Expression of an electrically silent voltage-gated potassium channel in the human placenta. J OBSTET GYNAECOL 2013; 32:624-9. [PMID: 22943705 DOI: 10.3109/01443615.2012.709288] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Human placental expression of K(V)9.3, a voltage-gated K channel linked to tissue oxygenation responses, has been suggested at the messenger RNA level but tissue localisation has not been described. We aimed to: (1) produce an antibody to human K(V)9.3 and (2) assess channel expression and distribution in human placental tissue. We determined human placental protein expression and localisation using an antibody to K(V)9.3. Antibody specificity was confirmed by Western blotting. Staining was observed in syncytiotrophoblast microvillous membrane, endothelial cells (in intermediate, stem villi and chorionic plate blood vessels) and vascular smooth muscle cells (large diameter vessels only) by immunohistochemistry. Expression was unchanged in tissue from women with small-for-gestational age babies. It was concluded that K(V)9.3 is localised to human placental vascular tissues and syncytiotrophoblast.
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Affiliation(s)
- G K Fyfe
- Maternal and Fetal Health Research Centre, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
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31
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Hur CG, Kim EJ, Cho SK, Cho YW, Yoon SY, Tak HM, Kim CW, Choe C, Han J, Kang D. K+ efflux through two-pore domain K+ channels is required for mouse embryonic development. Reproduction 2012; 143:625-36. [DOI: 10.1530/rep-11-0225] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Numerous studies have suggested that K+ channels regulate a wide range of physiological processes in mammalian cells. However, little is known about the specific function of K+ channels in germ cells. In this study, mouse zygotes were cultured in a medium containing K+ channel blockers to identify the functional role of K+ channels in mouse embryonic development. Voltage-dependent K+ channel blockers, such as tetraethylammonium and BaCl2, had no effect on embryonic development to the blastocyst stage, whereas K2P channel blockers, such as quinine, selective serotonin reuptake inhibitors (fluoxetine, paroxetine, and citalopram), gadolinium trichloride, anandamide, ruthenium red, and zinc chloride, significantly decreased blastocyst formation (P<0.05). RT-PCR data showed that members of the K2P channel family, specifically KCNK2, KCNK10, KCNK4, KCNK3, and KCNK9, were expressed in mouse oocytes and embryos. In addition, their mRNA expression levels, except Kcnk3, were up-regulated by above ninefold in morula-stage embryos compared with 2-cell stage embryos (2-cells). Immunocytochemical data showed that KCNK2, KCNK10, KCNK4, KCNK3, and KCNK9 channel proteins were expressed in the membrane of oocytes, 2-cells, and blastocysts. Each siRNA injection targeted at Kcnk2, Kcnk10, Kcnk4, Kcnk3, and Kcnk9 significantly decreased blastocyst formation by ∼38% compared with scrambled siRNA injection (P<0.05). The blockade of K2P channels acidified the intracellular pH and depolarized the membrane potential. These results suggest that K2P channels could improve mouse embryonic development through the modulation of gating by activators.
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32
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Hristov KL, Chen M, Soder RP, Parajuli SP, Cheng Q, Kellett WF, Petkov GV. KV2.1 and electrically silent KV channel subunits control excitability and contractility of guinea pig detrusor smooth muscle. Am J Physiol Cell Physiol 2011; 302:C360-72. [PMID: 21998137 DOI: 10.1152/ajpcell.00303.2010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Voltage-gated K(+) (K(V)) channels are implicated in detrusor smooth muscle (DSM) function. However, little is known about the functional role of the heterotetrameric K(V) channels in DSM. In this report, we provide molecular, electrophysiological, and functional evidence for the presence of K(V)2.1 and electrically silent K(V) channel subunits in guinea pig DSM. Stromatoxin-1 (ScTx1), a selective inhibitor of the homotetrameric K(V)2.1, K(V)2.2, and K(V)4.2 as well as the heterotetrameric K(V)2.1/6.3 and K(V)2.1/9.3 channels, was used to examine the role of these K(V) channels in DSM function. RT-PCR indicated mRNA expression of K(V)2.1, K(V)6.2-6.3, K(V)8.2, and K(V)9.1-9.3 subunits in isolated DSM cells. K(V)2.1 protein expression was confirmed by Western blot and immunocytochemistry. Perforated whole cell patch-clamp experiments revealed that ScTx1 (100 nM) inhibited the amplitude of the K(V) current in freshly isolated DSM cells. ScTx1 (100 nM) did not significantly change the steady-state activation and inactivation curves for K(V) current. However, ScTx1 (100 nM) decreased the activation time-constant of the K(V) current at positive voltages. Although our patch-clamp data could not exclude the presence of the homotetrameric K(V)2.1 channels, the biophysical characteristics of the ScTx1-sensitive current were consistent with the presence of heterotetrameric K(V)2.1/silent K(V) channels. Current-clamp recordings showed that ScTx1 (100 nM) did not change the DSM cell resting membrane potential. ScTx1 (100 nM) increased the spontaneous phasic contraction amplitude, muscle force, and muscle tone as well as the amplitude of the electrical field stimulation-induced contractions of isolated DSM strips. Collectively, our data revealed that K(V)2.1-containing channels are important physiological regulators of guinea pig DSM excitability and contractility.
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Affiliation(s)
- Kiril L Hristov
- Department of Pharmaceutical and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, USA
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Mistry HD, McCallum LA, Kurlak LO, Greenwood IA, Broughton Pipkin F, Tribe RM. Novel expression and regulation of voltage-dependent potassium channels in placentas from women with preeclampsia. Hypertension 2011; 58:497-504. [PMID: 21730298 DOI: 10.1161/hypertensionaha.111.173740] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Preeclampsia is associated with structural/functional alterations in placental and maternal vasculature. Voltage-dependant potassium channels encoded by KCNQ1-5 genes have been detected in several types of blood vessels where they promote vascular relaxation. Voltage-dependant potassium channel function can be modulated by KCNE1-5-encoded accessory proteins. The aim of this study was to determine whether KCNQ and KCNE genes are differentially expressed in placentas from women with preeclampsia compared with normotensive controls and to examine any differences in those who delivered preterm (<37 weeks) or term. Placental biopsies (from midway between the cord and periphery) were obtained, with consent, from white European control (n=24; term) and preeclamptic (n=22; of whom 8 delivered before 37 weeks' gestation) women. KCNQ/KCNE and GAPDH mRNA expressions were determined by quantitative RT-PCR. Protein expression/localization was assessed using immunohistochemistry. KCNQ3 and KCNE5 mRNA expressions were significantly upregulated in preeclampsia (median [interquartile range]: 1.942 [0.905 to 3.379]) versus controls (0.159 [0.088 to 0.288]; P=0.001) and exhibited a strong positive correlation with each other (P<0.001), suggesting a novel heterodimer. Enhanced protein expression of KCNQ3 and KCNE5 in preeclampsia was confirmed with localization mainly restricted to the syncytiotrophoblast. KCNQ4 and KCNE1 isoforms were suppressed in placentas from term preeclamptic women versus controls (P≤0.05). KCNQ1 mRNA expression was increased and KCNQ5 decreased in the preterm preeclamptic group versus controls (P<0.05). In summary, voltage-dependant potassium channels are expressed and markedly modulated in placentas from preeclamptic women. Differential expression of isoforms may lead to altered cell proliferation. The correlation between KCNQ3 and KCNE5 expression is indicative of a novel channel complex and warrants further investigation.
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Affiliation(s)
- Hiten D Mistry
- Maternal and Fetal Research Unit, Division of Women's Health, King's College London, St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, UK.
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Wareing M, Greenwood SL. Review: Potassium channels in the human fetoplacental vasculature. Placenta 2011; 32 Suppl 2:S203-6. [PMID: 21227507 DOI: 10.1016/j.placenta.2010.12.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 12/16/2010] [Accepted: 12/16/2010] [Indexed: 01/12/2023]
Abstract
Despite their fundamental importance for normal cellular function, potassium (K) channels have been poorly studied in placental vascular tissues. This lack of experimental focus may relate to the fact that, as yet, no pregnancy complications have been directly attributable to a specific "channelopathy". K channel activity is central to normal cellular function. Vascular smooth muscle and endothelial cells within the fetoplacental circulation would be expected to be heavily influenced by the behaviour of K channels, as has been well-documented in other vascular beds. In this review, we summarise current understanding of K channel expression and activity in fetoplacental vasculature in normal and complicated pregnancies.
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Affiliation(s)
- M Wareing
- Maternal and Fetal Health Research Centre, School of Biomedicine, The University of Manchester, St. Mary's Hospital, Manchester, UK.
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35
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Mechanism of Kv2.1 channel inhibition by a selective COX-2 inhibitor SC-791—modification of gating. Brain Res 2010; 1359:67-74. [DOI: 10.1016/j.brainres.2010.08.062] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2010] [Revised: 08/18/2010] [Accepted: 08/20/2010] [Indexed: 11/22/2022]
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36
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Zhong XZ, Abd-Elrahman KS, Liao CH, El-Yazbi AF, Walsh EJ, Walsh MP, Cole WC. Stromatoxin-sensitive, heteromultimeric Kv2.1/Kv9.3 channels contribute to myogenic control of cerebral arterial diameter. J Physiol 2010; 588:4519-37. [PMID: 20876197 DOI: 10.1113/jphysiol.2010.196618] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Cerebral vascular smooth muscle contractility plays a crucial role in controlling arterial diameter and, thereby, blood flow regulation in the brain. A number of K(+) channels have been suggested to contribute to the regulation of diameter by controlling smooth muscle membrane potential (E(m)) and Ca(2+) influx. Previous studies indicate that stromatoxin (ScTx1)-sensitive, Kv2-containing channels contribute to the control of cerebral arterial diameter at 80 mmHg, but their precise role and molecular composition were not determined. Here, we tested if Kv2 subunits associate with 'silent' subunits from the Kv5, Kv6, Kv8 or Kv9 subfamilies to form heterotetrameric channels that contribute to control of diameter of rat middle cerebral arteries (RMCAs) over a range of intraluminal pressure from 10 to 100 mmHg. The predominant mRNAs expressed by RMCAs encode Kv2.1 and Kv9.3 subunits. Co-localization of Kv2.1 and Kv9.3 proteins at the plasma membrane of dissociated single RMCA myocytes was detected by proximity ligation assay. ScTx1-sensitive native current of RMCA myocytes and Kv2.1/Kv9.3 currents exhibited functional identity based on the similarity of their deactivation kinetics and voltage dependence of activation that were distinct from those of homomultimeric Kv2.1 channels. ScTx1 treatment enhanced the myogenic response of pressurized RMCAs between 40 and 100 mmHg, but this toxin also caused constriction between 10 and 40 mmHg that was not previously observed following inhibition of large conductance Ca(2+)-activated K(+) (BK(Ca)) and Kv1 channels. Taken together, this study defines the molecular basis of Kv2-containing channels and contributes to our understanding of the functional significance of their expression in cerebral vasculature. Specifically, our findings provide the first evidence of heteromultimeric Kv2.1/Kv9.3 channel expression in RMCA myocytes and their distinct contribution to control of cerebral arterial diameter over a wider range of E(m) and transmural pressure than Kv1 or BK(Ca) channels owing to their negative range of voltage-dependent activation.
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Affiliation(s)
- Xi Zoë Zhong
- The Smooth Muscle Research Group, Department of Physiology and Pharmacology, Faculty of Medicine, University of Calgary, 3330 Hospital Drive N.W., Calgary, Alberta, Canada T2N 4N1
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37
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Madeja M, Steffen W, Mesic I, Garic B, Zhorov BS. Overlapping binding sites of structurally different antiarrhythmics flecainide and propafenone in the subunit interface of potassium channel Kv2.1. J Biol Chem 2010; 285:33898-905. [PMID: 20709754 DOI: 10.1074/jbc.m110.159897] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Kv2.1 channels, which are expressed in brain, heart, pancreas, and other organs and tissues, are important targets for drug design. Flecainide and propafenone are known to block Kv2.1 channels more potently than other Kv channels. Here, we sought to explore structural determinants of this selectivity. We demonstrated that flecainide reduced the K(+) currents through Kv2.1 channels expressed in Xenopus laevis oocytes in a voltage- and time-dependent manner. By systematically exchanging various segments of Kv2.1 with those from Kv1.2, we determined flecainide-sensing residues in the P-helix and inner helix S6. These residues are not exposed to the inner pore, a conventional binding region of open channel blockers. The flecainide-sensing residues also contribute to propafenone binding, suggesting overlapping receptors for the drugs. Indeed, propafenone and flecainide compete for binding in Kv2.1. We further used Monte Carlo-energy minimizations to map the receptors of the drugs. Flecainide docking in the Kv1.2-based homology model of Kv2.1 predicts the ligand ammonium group in the central cavity and the benzamide moiety in a niche between S6 and the P-helix. Propafenone also binds in the niche. Its carbonyl group accepts an H-bond from the P-helix, the amino group donates an H-bond to the P-loop turn, whereas the propyl group protrudes in the pore and blocks the access to the selectivity filter. Thus, besides the binding region in the central cavity, certain K(+) channel ligands can expand in the subunit interface whose residues are less conserved between K(+) channels and hence may be targets for design of highly desirable subtype-specific K(+) channel drugs.
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Affiliation(s)
- Michael Madeja
- Institute of Physiology, University of Münster, Münster, Germany.
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Kiernan M, Barrie A, Szkolar J, Mills T, Wareing M. Functional Evidence for Oxygen-Sensitive Voltage-Gated Potassium Channels in Human Placental Vasculature. Placenta 2010; 31:553-5. [DOI: 10.1016/j.placenta.2010.03.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 03/16/2010] [Accepted: 03/16/2010] [Indexed: 10/19/2022]
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Frolov RV, Bondarenko VE, Singh S. Mechanisms of Kv2.1 channel inhibition by celecoxib--modification of gating and channel block. Br J Pharmacol 2009; 159:405-18. [PMID: 20015088 DOI: 10.1111/j.1476-5381.2009.00539.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Selective cyclooxygenase-2 (COX-2) inhibitors such as rofecoxib (Vioxx) and celecoxib (Celebrex) were developed as NSAIDs with reduced gastric side effects. Celecoxib has now been shown to affect cellular physiology via an unexpected, COX-independent, pathway - by inhibiting K(v)2.1 and other ion channels. In this study, we investigated the mechanism of the action of celecoxib on K(v)2.1 channels. EXPERIMENTAL APPROACH The mode of action of celecoxib on rat K(v)2.1 channels was studied by whole-cell patch-clamping to record currents from channels expressed in HEK-293 cells. KEY RESULTS Celecoxib reduced current through K(v)2.1 channels when applied from the extracellular side. At low concentrations (<or=3 microM), celecoxib accelerated kinetics of activation, deactivation and inactivation. Recovery of rat K(v)2.1 channels from inactivation could be characterized by two components, with celecoxib selectively accelerating the slow component of recovery at <or=10 microM. At >3 microM, celecoxib led to closed-channel block with relative slowing of activation. At 30 microM, it additionally induced open-channel block that manifested in use-dependent inhibition and slower recovery from inactivation. CONCLUSIONS AND IMPLICATIONS Celecoxib reduced current through K(v)2.1 channels by modifying gating and inducing closed- and open-channel block, with the three effects manifesting at different concentrations. These data will help to elucidate the mechanisms of action of this widely prescribed drug on ion channels and those underlying its neurological, cardiovascular and other effects.
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Affiliation(s)
- R V Frolov
- Department of Pharmacology and Toxicology, State University of New York, Buffalo, New York 14214-3000, USA
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40
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Corcoran J, Lacey H, Baker PN, Wareing M. Altered Potassium Channel Expression in the Human Placental Vasculature of Pregnancies Complicated by Fetal Growth Restriction. Hypertens Pregnancy 2009; 27:75-86. [DOI: 10.1080/10641950701826158] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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41
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Eichhorn B, Muller G, Leuner A, Sawamura T, Ravens U, Morawietz H. Impaired vascular function in small resistance arteries of LOX-1 overexpressing mice on high-fat diet. Cardiovasc Res 2009; 82:493-502. [PMID: 19289377 DOI: 10.1093/cvr/cvp089] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
AIMS LOX-1 is a major vascular receptor for oxidized low-density lipoprotein (oxLDL). In this study, we analysed the impact of LOX-1 overexpression and high dietary fat intake on vascular function in small resistance arteries. METHODS AND RESULTS Relaxation of mesenteric arteries was measured using a wire myograph. Compared with the control group, mice overexpressing LOX-1 on a high-fat diet (FD) had preserved vascular smooth muscle relaxation, but impaired endothelium-dependent relaxation via NO. Vascular NO availability was decreased by exaggerated formation of reactive oxygen species and decreased endothelial NO synthase expression. Endothelium-derived hyperpolarizing factor (EDHF)-mediated relaxation via cytochrome P450 metabolites was increased in LOX-1 + FD animals, but did not completely compensate for the loss of NO. Currents of calcium-activated potassium channels with large conductance (BKCa channels) were measured by the voltage-clamp method. The BKCa current amplitudes were not altered in endothelial cells, but highly increased in vascular smooth muscle cells from resistance arteries of LOX-1-overexpressing mice on FD. BK(Ca) currents were activated by low-dose H2O2 and cytochrome P450 metabolites 11,12-EET and 14,15-EET as EDHF in control mice. CONCLUSION LOX-1 overexpression and FD caused functional changes in endothelial and vascular smooth muscle cells of small resistance arteries.
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Affiliation(s)
- Birgit Eichhorn
- Department of Pharmacology and Toxicology, Medical Faculty Carl Gustav Carus, University of Technology, Fetscherstr. 74, D-01307 Dresden, Germany.
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42
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Kwan HY, Shen B, Ma X, Kwok YC, Huang Y, Man YB, Yu S, Yao X. TRPC1 Associates With BK
Ca
Channel to Form a Signal Complex in Vascular Smooth Muscle Cells. Circ Res 2009; 104:670-8. [DOI: 10.1161/circresaha.108.188748] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
TRPC1 (transient receptor potential canonical 1) is a Ca
2+
-permeable cation channel involved in diverse physiological function. TRPC1 may associate with other proteins to form a signaling complex, which is crucial for channel function. In the present study, we investigated the interaction between TRPC1 and large conductance Ca
2+
-sensitive K
+
channel (BK
Ca
). With the use of potentiometric fluorescence dye DiBAC
4
(3), we found that store-operated Ca
2+
influx resulted in membrane hyperpolarization of vascular smooth muscle cells (VSMCs). The hyperpolarization was inhibited by an anti-TRPC1 blocking antibody T1E3 and 2 BK
Ca
channel blockers, charybdotoxin and iberiotoxin. These data were confirmed by sharp microelectrode measurement of membrane potential in VSMCs of intact arteries. Furthermore, T1E3 treatment markedly enhanced the membrane depolarization and contraction of VSMCs in response to several contractile agonists including phenylephrine, endothelin-1, and U-46619. In coimmunoprecipitation experiments, an antibody against BK
Ca
α-subunit [BK
Ca
(α)] could pull down TRPC1, and moreover an anti-TRPC1 antibody could reciprocally pull down BK
Ca
(α). Double-labeling immunocytochemistry showed that TRPC1 and BK
Ca
were colocalized in the same subcellular regions, mainly on the plasma membrane, in VSMCs. These data suggest that, TRPC1 physically associates with BK
Ca
in VSMCs and that Ca
2+
influx through TRPC1 activates BK
Ca
to induce membrane hyperpolarization. The hyperpolarizing effect of TRPC1-BK
Ca
coupling could serve to reduce agonist-induced membrane depolarization, thereby preventing excessive contraction of VSMCs to contractile agonists.
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Affiliation(s)
- Hiu-Yee Kwan
- From the Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, Faculty of Medicine, the Chinese University of Hong Kong
| | - Bing Shen
- From the Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, Faculty of Medicine, the Chinese University of Hong Kong
| | - Xin Ma
- From the Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, Faculty of Medicine, the Chinese University of Hong Kong
| | - Yuk-Chi Kwok
- From the Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, Faculty of Medicine, the Chinese University of Hong Kong
| | - Yu Huang
- From the Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, Faculty of Medicine, the Chinese University of Hong Kong
| | - Yu-Bun Man
- From the Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, Faculty of Medicine, the Chinese University of Hong Kong
| | - Shan Yu
- From the Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, Faculty of Medicine, the Chinese University of Hong Kong
| | - Xiaoqiang Yao
- From the Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, Faculty of Medicine, the Chinese University of Hong Kong
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Hayoz S, Bychkov R, Serir K, Docquier M, Bény JL. Purinergic activation of a leak potassium current in freshly dissociated myocytes from mouse thoracic aorta. Acta Physiol (Oxf) 2009; 195:247-58. [PMID: 18616685 DOI: 10.1111/j.1748-1716.2008.01884.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM Exogenous ATP elicits a delayed calcium-independent K(+) current on freshly isolated mouse thoracic aorta myocytes. We investigated the receptor, the intracellular pathway and the nature of this current. METHODS The patch-clamp technique was used to record ATP-elicited delayed K(+) current in freshly dissociated myocytes. RESULTS ATP-elicited delayed K(+) current was not inhibited by a 'cocktail' of K(+) channel blockers (4-AP, TEA, apamin, charybdotoxin, glibenclamide). The amplitude of the delayed K(+) current decreased after the reduction of extracellular pH from 7.4 to 6.5. These two characteristics suggest that this current could be carried by the TASK subfamily of 'twin-pore potassium channels' (K2P). Purinergic agonists including dATP, but not ADP, activated the delayed K(+) current, indicating that P2Y(11) is the likely receptor involved in its activation. The PKC activator phorbol ester 12,13-didecanoate stimulated this current. In addition, the PKC inhibitor Gö 6850 partially inhibited it. Real-time quantitative PCR showed that the genes encoding TASK-1 and TASK-2 are expressed. CONCLUSION Our results indicate that blocker cocktail-insensitive delayed K(+) current in freshly dissociated aortic myocytes is probably carried by the TASK subfamily of twin-pore channels.
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Affiliation(s)
- S Hayoz
- Department of Zoology and Animal Biology, University of Geneva, Sciences III, Geneva, Switzerland
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Hur CG, Choe C, Kim GT, Cho SK, Park JY, Hong SG, Han J, Kang D. Expression and localization of two-pore domain K(+) channels in bovine germ cells. Reproduction 2008; 137:237-44. [PMID: 18987255 DOI: 10.1530/rep-08-0035] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Two-pore domain K(+) (K(2P)) channels that help set the resting membrane potential of excitable and nonexcitable cells are expressed in many kinds of cells and tissues. However, the expression of K(2P) channels has not yet been reported in bovine germ cells. In this study, we demonstrate for the first time that K(2P) channels are expressed in the reproductive organs and germ cells of Korean cattle. RT-PCR data showed that members of the K(2P) channel family, specifically KCNK3, KCNK9, KCNK2, KCNK10, and KCNK4, were expressed in the ovary, testis, oocytes, embryo, and sperm. Out of these channels, KCNK2 and KCNK4 mRNAs were abundantly expressed in the mature oocytes, eight-cell stage embryos, and blastocysts compared with immature oocytes. KCNK4 and KCNK3 were significantly increased in eight-cell stage embryos. Immunocytochemical data showed that KCNK2, KCNK10, KCNK4, KCNK3, and KCNK9 channel proteins were expressed at the membrane of oocytes and blastocysts. KCNK10 and KCNK4 were strongly expressed and distributed in oocyte membranes. These channel proteins were also localized to the acrosome sperm cap. In particular, KCNK3 and KCNK4 were strongly localized to the post-acrosomal region of the sperm head and the equatorial band within the sperm head respectively. These results suggest that K(2P) channels might contribute to the background K(+) conductance of germ cells and regulate various physiological processes, such as maturation, fertilization, and development.
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Affiliation(s)
- Chang-Gi Hur
- CHO-A Biotechnology Research Institute, CHO-A Pharmaceutical Company Ltd, Seoul, South Korea
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45
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Gurney A, Manoury B. Two-pore potassium channels in the cardiovascular system. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2008; 38:305-18. [DOI: 10.1007/s00249-008-0326-8] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Revised: 03/31/2008] [Accepted: 04/02/2008] [Indexed: 12/24/2022]
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Mills TA, Baker PN, Wareing M. The effect of mode of delivery on placental chorionic plate vascular reactivity. Hypertens Pregnancy 2007; 26:201-10. [PMID: 17469010 DOI: 10.1080/10601330701274824] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
OBJECTIVE To determine whether delivery mode influences placental chorionic plate arterial and venous vascular reactivity. METHODS Normal term placentas were obtained after vaginal delivery or cesarean section. Chorionic plate arterial and venous function was assessed by wire myography. RESULTS Sodium nitroprusside-induced arterial relaxation increased post cesarean section at 20% oxygen. Decreased U46619-induced venous contraction was observed in vaginal deliveries at 7% oxygen. Sodium nitroprusside-induced relaxation increased in vaginal delivery at 20% oxygen. CONCLUSION Delivery mode does not alter chorionic plate arterial vascular reactivity under physiological conditions, however venous reactivity was modified, a factor for consideration when interpreting functional experimental data.
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Affiliation(s)
- Tracey A Mills
- Division of Human Development, The University of Manchester, Manchester, UK.
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Hsu SS, Huang CJ, Cheng HH, Chou CT, Lee HY, Wang JL, Chen IS, Liu SI, Lu YC, Chang HT, Huang JK, Chen JS, Jan CR. Anandamide-induced Ca2+ elevation leading to p38 MAPK phosphorylation and subsequent cell death via apoptosis in human osteosarcoma cells. Toxicology 2007; 231:21-9. [PMID: 17222495 DOI: 10.1016/j.tox.2006.11.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Revised: 10/18/2006] [Accepted: 11/07/2006] [Indexed: 10/23/2022]
Abstract
The effect of anandamide on human osteoblasts is unclear. This study examined the effect of anandamide on viability, apoptosis, mitogen-activated protein kinases (MAPKs) and Ca2+ levels in MG63 osteosarcoma cells. Anandamide at 50-200 microM decreased cell viability via apoptosis as demonstrated by propidium iodide staining and activation of caspase-3. Immunoblotting suggested that anandamide induced expression of ERK, JNK and p38 MAPK. Anandamide-induced cell death and apoptosis were reversed by SB203580, but not by PD98059 and SP600125, suggesting that anandamide's action was via p38 MAPK, but not via ERK and JNK. Anandamide at 1-100 microM induced [Ca2+]i increases. Removal of extracellular Ca2+ decreased the anandamide response, indicating that anandamide induced Ca2+ influx and Ca2+ release. Chelation of intracellular Ca2+ with BAPTA reversed anandamide-induced cell death and p38 MAPK phosphorylation. Collectively, in MG63 cells, anandamide induced [Ca2+]i increases which evoked p38 MAPK phosphorylation. This p38 MAPK phosphorylation subsequently activated caspase-3 leading to apoptosis.
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Affiliation(s)
- Shu-Shong Hsu
- Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan
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48
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Jewsbury S, Baker PN, Wareing M. Relaxation of human placental arteries and veins by ATP-sensitive potassium channel openers. Eur J Clin Invest 2007; 37:65-72. [PMID: 17181569 DOI: 10.1111/j.1365-2362.2007.01749.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Adenosine triphosphate (ATP)-sensitive potassium channels (K(ATP)) are important modulators of vascular tone. Preliminary data from our laboratory suggests that K(ATP) channels are expressed in the fetoplacental vasculature where addition of pinacidil, a specific K(ATP) opener, promotes relaxation. We aimed to assess the effects of KRN2391 and KRN4884 on the fetoplacental vasculature, which are putative K(ATP) channel openers. MATERIALS AND METHODS Functional activity of K(ATP) channels was assessed in chorionic plate arteries and veins using wire myography. Cromakalim-, KRN2391- and KRN4884-induced relaxations were assessed in the presence and absence of agonist-induced pretone. Cromakalim, an established K(ATP) channel opener, acted as control. RESULTS KRN2391 evoked significantly greater relaxation of chorionic plate arteries and veins than either KRN4884 or cromakalim. KRN2391-induced relaxation of precontracted arteries and veins was reduced in the presence of inhibitors of the nitric oxide pathway (L-NNA or LY83583). With KRN4884, there was no contribution of nitric oxide to the induced relaxation. CONCLUSIONS We conclude that K(ATP) channels play an important role in controlling placental vascular tone. KRN2391 induces relaxation of human placental blood vessels by activation of K(ATP) channels and via activation of nitric oxide-dependent pathways.
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Affiliation(s)
- S Jewsbury
- The University of Manchester, St. Mary's Hospital, Hathersage Road, Manchester M13 0JH, UK
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49
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Wareing M, Greenwood SL, Fyfe GK, Baker PN. Reactivity of Human Placental Chorionic Plate Vessels from Pregnancies Complicated by Intrauterine Growth Restriction (IUGR)1. Biol Reprod 2006; 75:518-23. [PMID: 16707770 DOI: 10.1095/biolreprod.106.051607] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
A successful pregnancy is dependent on liberal placental perfusion via the maternal and fetal circulations. Doppler waveform analyses of umbilical arteries suggest increased resistance to flow in the fetoplacental circulation of pregnancies complicated by intrauterine growth restriction (IUGR). Neither the site nor the mediators responsible for this altered vascular reactivity are known, to date. In placentas in normal pregnancy, reduced oxygenation promotes contraction of the in vitro-perfused placental cotyledon and modulates agonist-induced contraction of chorionic plate arteries and veins. Placental oxygenation has also been suggested to be reduced in IUGR. We tested the hypothesis that oxygen tension could directly modify placental chorionic plate vessel vasoreactivity in IUGR. Small arteries and veins from the chorionic plate were dissected from biopsies from placentas of pregnancies complicated by IUGR and were studied using parallel wire myography. Vasoconstriction at 20%, 7%, and 2% oxygen was assessed utilizing the thromboxane mimetic U46619. Experiments were also performed in the presence of 4-aminopyridine (4AP), a blocker of voltage-gated potassium channels. Increased oxygenation reduced venous vasoconstriction but did not modify arterial vasoconstriction. 4AP increased basal tone in arteries and veins. We suggest that venoconstriction in response to hypoxia may provide a mechanism for increased fetoplacental vascular resistance associated with IUGR.
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Affiliation(s)
- Mark Wareing
- Division of Human Development, Maternal and Fetal Health Research Center, The University of Manchester, St. Mary's Hospital, Manchester M13 0JH, United Kingdom.
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