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Shen X, Zhang L, Jiang L, Xiong W, Tang Y, Lin L, Yu T. Alteration of sphingosine-1-phosphate with aging induces contractile dysfunction of colonic smooth muscle cells via Ca 2+ -activated K + channel (BK Ca ) upregulation. Neurogastroenterol Motil 2021; 33:e14052. [PMID: 33452855 DOI: 10.1111/nmo.14052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/13/2020] [Accepted: 11/13/2020] [Indexed: 02/04/2023]
Abstract
BACKGROUND Age-associated changes alter calcium-activated potassium channel (BKCa ) expression of colon. Sphingolipids (SLs) are important cell membrane structural components; altered composition of SLs may affect BKCa expression. This study investigated the mechanism by which sphingosine-1-phosphate (S1P) contributes to age-associated contractile dysfunction. METHODS Fifty male Sprague Dawley rats of different ages were randomly assigned to five age-groups, namely 3, 6, 12, 18, and 24 months. BKCa expression, S1P levels, and phosphorylated myosin light chain (p-MLC) levels were tested in colonic tissues. In the absence and presence of S1P treatment, BKCa expression, p-MLC levels, and intracellular calcium mobilization were tested in vitro. BKCa small interfering RNA (siRNA) was used to investigate whether p-MLC expression and calcium mobilization were affected by BKCa in colonic smooth muscle cells (SMCs). The expressions of phosphorylated protein kinase B, c-Jun N-terminal kinases (JNKs), extracellular-regulated protein kinases, nuclear factor kappa-B (NF-κB), and protein kinase Cζ (PKCζ ) were examined to investigate the correlation between S1P and BKCa . KEY RESULTS Sphingosine-1-phosphate levels and sphingosine-1-phosphate receptor 2 (S1PR2) and BKCa expressions were upregulated and p-MLC expression was downregulated in the colonic tissues, age dependently. In the cultured SMCs, S1P treatment increased BKCa expression and reduced calcium concentration and p-MLC was observed. BKCa siRNA increased calcium concentration, and p-MLC levels significantly compared with control. We also showed that S1P upregulated BKCa through PKCζ , JNK, and NF-κB pathways. CONCLUSIONS AND INFERENCES In conclusion, S1P and S1PR2 participate in age-associated contractile dysfunction via BKCa upregulation through PKCζ , JNK, and NF-κB pathways.
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Affiliation(s)
- Xiaoxue Shen
- Department of Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Ling Zhang
- Department of Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Ling Jiang
- Department of Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Wenjie Xiong
- Department of Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yurong Tang
- Department of Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Lin Lin
- Department of Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Ting Yu
- Department of Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
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Permissive Modulation of Sphingosine-1-Phosphate-Enhanced Intracellular Calcium on BK Ca Channel of Chromaffin Cells. Int J Mol Sci 2021; 22:ijms22042175. [PMID: 33671654 PMCID: PMC7926978 DOI: 10.3390/ijms22042175] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/10/2021] [Accepted: 02/18/2021] [Indexed: 12/18/2022] Open
Abstract
Sphingosine-1-phosphate (S1P), is a signaling sphingolipid which acts as a bioactive lipid mediator. We assessed whether S1P had multiplex effects in regulating the large-conductance Ca2+-activated K+ channel (BKCa) in catecholamine-secreting chromaffin cells. Using multiple patch-clamp modes, Ca2+ imaging, and computational modeling, we evaluated the effects of S1P on the Ca2+-activated K+ currents (IK(Ca)) in bovine adrenal chromaffin cells and in a pheochromocytoma cell line (PC12). In outside-out patches, the open probability of BKCa channel was reduced with a mean-closed time increment, but without a conductance change in response to a low-concentration S1P (1 µM). The intracellular Ca2+ concentration (Cai) was elevated in response to a high-dose (10 µM) but not low-dose of S1P. The single-channel activity of BKCa was also enhanced by S1P (10 µM) in the cell-attached recording of chromaffin cells. In the whole-cell voltage-clamp, a low-dose S1P (1 µM) suppressed IK(Ca), whereas a high-dose S1P (10 µM) produced a biphasic response in the amplitude of IK(Ca), i.e., an initial decrease followed by a sustained increase. The S1P-induced IK(Ca) enhancement was abolished by BAPTA. Current-clamp studies showed that S1P (1 µM) increased the action potential (AP) firing. Simulation data revealed that the decreased BKCa conductance leads to increased AP firings in a modeling chromaffin cell. Over a similar dosage range, S1P (1 µM) inhibited IK(Ca) and the permissive role of S1P on the BKCa activity was also effectively observed in the PC12 cell system. The S1P-mediated IK(Ca) stimulation may result from the elevated Cai, whereas the inhibition of BKCa activity by S1P appears to be direct. By the differentiated tailoring BKCa channel function, S1P can modulate stimulus-secretion coupling in chromaffin cells.
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Alganga H, Almabrouk TAM, Katwan OJ, Daly CJ, Pyne S, Pyne NJ, Kennedy S. Short Periods of Hypoxia Upregulate Sphingosine Kinase 1 and Increase Vasodilation of Arteries to Sphingosine 1-Phosphate (S1P) via S1P 3. J Pharmacol Exp Ther 2019; 371:63-74. [PMID: 31371480 DOI: 10.1124/jpet.119.257931] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 07/30/2019] [Indexed: 02/06/2023] Open
Abstract
Sphingosine kinase [(SK), isoforms SK1 and SK2] catalyzes the formation of the bioactive lipid, sphingosine 1-phosphate (S1P). This can be exported from cells and bind to S1P receptors to modulate vascular function. We investigated the effect of short-term hypoxia on SK1 expression and the response of arteries to S1P. SK1 expression in rat aortic and coronary artery endothelial cells was studied using immunofluorescence and confocal microscopy. Responses of rat aortic rings were studied using wire myography and reversible hypoxia induced by bubbling myography chambers with 95% N2:5% CO2 Inhibitors were added 30 minutes before induction of hypoxia. S1P induced endothelium-dependent vasodilation via activation of S1P3 receptors and generation of nitric oxide. Hypoxia significantly increased relaxation to S1P and this was attenuated by (2R)-1-[[(4-[[3-methyl-5-[(phenylsulfonyl)methyl] phenoxy]methyl]phenyl]methyl]-2-pyrrolidinemethanol [(PF-543), SK1 inhibitor] but not (R)-FTY720 methyl ether [(ROMe), SK2 inhibitor]. Hypoxia also increased vessel contractility to the thromboxane mimetic, 9,11-dideoxy-11α,9α-epoxymethanoprostaglandin F2α, which was further increased by PF-543 and ROMe. Hypoxia upregulated SK1 expression in aortic and coronary artery endothelial cells and this was blocked by PF-543 and 2-(p-hydroxyanilino)-4-(p-chlorophenyl)thiazole [(SKi), SK1/2 inhibitor]. The effects of PF-543 and SKi were associated with increased proteasomal/lysosomal degradation of SK1. A short period of hypoxia increases the expression of SK1, which may generate S1P to oppose vessel contraction. Under hypoxic conditions, upregulation of SK1 is likely to lead to increased export of S1P from the cell and vasodilation via activation of endothelial S1P3 receptors. These data have significance for perfusion of tissue during episodes of ischemia.
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Affiliation(s)
- H Alganga
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom (H.A., T.A.M.A., O.J.K., C.J.D., S.K.); Strathclyde Institute of Pharmacy and Biomedical Science, University of Strathclyde, Glasgow, United Kingdom (S.P., N.J.P.); Department of Pharmacology, School of Medicine, University of Zawia, Zawia, Libya (H.A., T.A.M.A.); and Department of Biochemistry, College of Medicine, University of Diyala, Baqubah, Iraq (O.J.K.)
| | - T A M Almabrouk
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom (H.A., T.A.M.A., O.J.K., C.J.D., S.K.); Strathclyde Institute of Pharmacy and Biomedical Science, University of Strathclyde, Glasgow, United Kingdom (S.P., N.J.P.); Department of Pharmacology, School of Medicine, University of Zawia, Zawia, Libya (H.A., T.A.M.A.); and Department of Biochemistry, College of Medicine, University of Diyala, Baqubah, Iraq (O.J.K.)
| | - O J Katwan
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom (H.A., T.A.M.A., O.J.K., C.J.D., S.K.); Strathclyde Institute of Pharmacy and Biomedical Science, University of Strathclyde, Glasgow, United Kingdom (S.P., N.J.P.); Department of Pharmacology, School of Medicine, University of Zawia, Zawia, Libya (H.A., T.A.M.A.); and Department of Biochemistry, College of Medicine, University of Diyala, Baqubah, Iraq (O.J.K.)
| | - C J Daly
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom (H.A., T.A.M.A., O.J.K., C.J.D., S.K.); Strathclyde Institute of Pharmacy and Biomedical Science, University of Strathclyde, Glasgow, United Kingdom (S.P., N.J.P.); Department of Pharmacology, School of Medicine, University of Zawia, Zawia, Libya (H.A., T.A.M.A.); and Department of Biochemistry, College of Medicine, University of Diyala, Baqubah, Iraq (O.J.K.)
| | - S Pyne
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom (H.A., T.A.M.A., O.J.K., C.J.D., S.K.); Strathclyde Institute of Pharmacy and Biomedical Science, University of Strathclyde, Glasgow, United Kingdom (S.P., N.J.P.); Department of Pharmacology, School of Medicine, University of Zawia, Zawia, Libya (H.A., T.A.M.A.); and Department of Biochemistry, College of Medicine, University of Diyala, Baqubah, Iraq (O.J.K.)
| | - N J Pyne
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom (H.A., T.A.M.A., O.J.K., C.J.D., S.K.); Strathclyde Institute of Pharmacy and Biomedical Science, University of Strathclyde, Glasgow, United Kingdom (S.P., N.J.P.); Department of Pharmacology, School of Medicine, University of Zawia, Zawia, Libya (H.A., T.A.M.A.); and Department of Biochemistry, College of Medicine, University of Diyala, Baqubah, Iraq (O.J.K.)
| | - S Kennedy
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom (H.A., T.A.M.A., O.J.K., C.J.D., S.K.); Strathclyde Institute of Pharmacy and Biomedical Science, University of Strathclyde, Glasgow, United Kingdom (S.P., N.J.P.); Department of Pharmacology, School of Medicine, University of Zawia, Zawia, Libya (H.A., T.A.M.A.); and Department of Biochemistry, College of Medicine, University of Diyala, Baqubah, Iraq (O.J.K.)
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Brini M, Leanza L, Szabo I. Lipid-Mediated Modulation of Intracellular Ion Channels and Redox State: Physiopathological Implications. Antioxid Redox Signal 2018; 28:949-972. [PMID: 28679281 DOI: 10.1089/ars.2017.7215] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Significance: Ion channels play an important role in the regulation of organelle function within the cell, as proven by increasing evidence pointing to a link between altered function of intracellular ion channels and different pathologies ranging from cancer to neurodegenerative diseases, ischemic damage, and lysosomal storage diseases. Recent Advances: A link between these pathologies and redox state as well as lipid homeostasis and ion channel function is in the focus of current research. Critical Issues: Ion channels are target of modulation by lipids and lipid messengers, although in most cases the mechanistic details have not been clarified yet. Ion channel function importantly impacts production of reactive oxygen species (ROS), especially in the case of mitochondria and lysosomes. ROS, in turn, may modulate the function of intracellular channels triggering thereby a feedback control under physiological conditions. If produced in excess, ROS can be harmful to lipids and may produce oxidized forms of these membrane constituents that ultimately affect ion channel function by triggering a "circulus vitiosus." Future Directions: The present review summarizes our current knowledge about the contribution of intracellular channels to oxidative stress and gives examples of how these channels are modulated by lipids and how this modulation may affect ROS production in ROS-related diseases. Future studies need to address the importance of the regulation of intracellular ion channels and related oxidative stress by lipids in various physiological and pathological contexts. Antioxid. Redox Signal. 28, 949-972.
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Affiliation(s)
- Marisa Brini
- Department of Biology, University of Padova, Padova, Italy
| | - Luigi Leanza
- Department of Biology, University of Padova, Padova, Italy
| | - Ildiko Szabo
- Department of Biology, University of Padova, Padova, Italy.,CNR Institute of Neuroscience, Padova, Italy
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Bondarenko AI, Panasiuk O, Drachuk K, Montecucco F, Brandt KJ, Mach F. The quest for endothelial atypical cannabinoid receptor: BK Ca channels act as cellular sensors for cannabinoids in in vitro and in situ endothelial cells. Vascul Pharmacol 2018; 102:44-55. [PMID: 29355732 PMCID: PMC6481560 DOI: 10.1016/j.vph.2018.01.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 01/10/2018] [Accepted: 01/16/2018] [Indexed: 12/20/2022]
Abstract
Endothelium-dependent component of cannabinoid-induced vasodilation has been postulated to require G-protein-coupled non-CB1/CB2 endothelial cannabinoid (eCB) receptor. GPR18 was proposed as a candidate for eCBR. To address the hypothesis that the effects attributed to eCBR are mediated by G-protein-coupled receptor (GPCR)-independent targets, we studied the electrical responses in endothelial cells, focusing on BKCa channels. In patches excised from endothelial-derived EA.hy926 cells, N-arachidonoyl glycine (NAGly) and abnormal cannabidiol (abn-cbd), prototypical agonists for eCB receptor, stimulate single BKCa activity in a concentration- and Ca2+-dependent manner. The postulated eCB receptor inhibitors rimonabant and AM251 were found to inhibit basal and stimulated by NAGly- and abn-cbd BKCa activity in cell-free patches. In isolated mice aortas, abn-cbd and NAGly produced endothelial cell hyperpolarization that was sensitive to paxilline, a selective BKCa inhibitor, but not to GPR18 antibody, and mimicked by NS1619, a direct BKCa opener. In excised patches from mice aortic endothelium, single channel activity with characteristics similar to BKCa was established by the addition of abn-cbd and NAGly. We conclude that the two cannabinoids abn-cbd and NAGly initiate a GPR18-independent activation of BKCa channels in mice aortic endothelial cells that might contribute to vasodilation to cannabinoids.
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Affiliation(s)
- Alexander I Bondarenko
- Circulatory Physiology Department, Bogomoletz Institute of Physiology NAS of Ukraine, Bogomoletz Str 4, Kiev 01024, Ukraine; Institute of Molecular Biology and Biochemistry, Medical University of Graz, Harrachgasse 21/III, Graz, 8010, Austria.
| | - Olga Panasiuk
- Circulatory Physiology Department, Bogomoletz Institute of Physiology NAS of Ukraine, Bogomoletz Str 4, Kiev 01024, Ukraine
| | - Konstantin Drachuk
- Circulatory Physiology Department, Bogomoletz Institute of Physiology NAS of Ukraine, Bogomoletz Str 4, Kiev 01024, Ukraine
| | - Fabrizio Montecucco
- First Clinic of Internal Medicine, Department of Internal Medicine, University of Genoa, 6 viale Benedetto XV, 16132 Genoa, Italy; Ospedale Policlinico San Martino, largo Benzi 10, 16132 Genoa, Italy; Centre of Excellence for Biomedical Research (CEBR), University of Genoa, 9 viale Benedetto XV, 16132 Genoa, Italy
| | - Karim J Brandt
- Division of Cardiology, Foundation for Medical Researches, Department of Internal Medicine, University of Geneva, Av. de la Roseraie 64, CH 1211, Geneva 4, Switzerland
| | - François Mach
- Division of Cardiology, Foundation for Medical Researches, Department of Internal Medicine, University of Geneva, Av. de la Roseraie 64, CH 1211, Geneva 4, Switzerland
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Shahin MH, Gong Y, Frye RF, Rotroff DM, Beitelshees AL, Baillie RA, Chapman AB, Gums JG, Turner ST, Boerwinkle E, Motsinger-Reif A, Fiehn O, Cooper-DeHoff RM, Han X, Kaddurah-Daouk R, Johnson JA. Sphingolipid Metabolic Pathway Impacts Thiazide Diuretics Blood Pressure Response: Insights From Genomics, Metabolomics, and Lipidomics. J Am Heart Assoc 2017; 7:e006656. [PMID: 29288159 PMCID: PMC5778957 DOI: 10.1161/jaha.117.006656] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 11/01/2017] [Indexed: 01/04/2023]
Abstract
BACKGROUND Although hydrochlorothiazide (HCTZ) is a well-established first-line antihypertensive in the United States, <50% of HCTZ treated patients achieve blood pressure (BP) control. Thus, identifying biomarkers that could predict the BP response to HCTZ is critically important. In this study, we utilized metabolomics, genomics, and lipidomics to identify novel pathways and biomarkers associated with HCTZ BP response. METHODS AND RESULTS First, we conducted a pathway analysis for 13 metabolites we recently identified to be significantly associated with HCTZ BP response. From this analysis, we found the sphingolipid metabolic pathway as the most significant pathway (P=5.8E-05). Testing 78 variants, within 14 genes involved in the sphingolipid metabolic canonical pathway, with the BP response to HCTZ identified variant rs6078905, within the SPTLC3 gene, as a novel biomarker significantly associated with the BP response to HCTZ in whites (n=228). We found that rs6078905 C-allele carriers had a better BP response to HCTZ versus noncarriers (∆SBP/∆DBP: -11.4/-6.9 versus -6.8/-3.5 mm Hg; ∆SBP P=6.7E-04; ∆DBP P=4.8E-04). Additionally, in blacks (n=148), we found genetic signals in the SPTLC3 genomic region significantly associated with the BP response to HCTZ (P<0.05). Last, we observed that rs6078905 significantly affects the baseline level of 4 sphingomyelins (N24:2, N24:3, N16:1, and N22:1; false discovery rate <0.05), from which N24:2 sphingomyelin has a significant correlation with both HCTZ DBP-response (r=-0.42; P=7E-03) and SBP-response (r=-0.36; P=2E-02). CONCLUSIONS This study provides insight into potential pharmacometabolomic and genetic mechanisms underlying HCTZ BP response and suggests that SPTLC3 is a potential determinant of the BP response to HCTZ. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00246519.
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Affiliation(s)
- Mohamed H Shahin
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Yan Gong
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Reginald F Frye
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Daniel M Rotroff
- Bioinformatics Research Center, North Carolina State University, Raleigh, NC
| | | | | | | | - John G Gums
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | | | - Eric Boerwinkle
- Human Genetics Center and Institute for Molecular Medicine, University of Texas Health Science Center, Houston, TX
| | | | - Oliver Fiehn
- Genome Center, University of California at Davis, CA
- Biochemistry Department, King Abdulaziz University, Jeddah, Saudi-Arabia
| | - Rhonda M Cooper-DeHoff
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
| | - Xianlin Han
- Sanford-Burnham Medical Research Institute, Orlando, FL
| | - Rima Kaddurah-Daouk
- Department of Psychiatry and Behavioural Sciences and Department of Medicine, Duke University, Durham, NC
| | - Julie A Johnson
- Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL
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Łukasiak A, Skup A, Chlopicki S, Łomnicka M, Kaczara P, Proniewski B, Szewczyk A, Wrzosek A. SERCA, complex I of the respiratory chain and ATP-synthase inhibition are involved in pleiotropic effects of NS1619 on endothelial cells. Eur J Pharmacol 2016; 786:137-147. [PMID: 27262382 DOI: 10.1016/j.ejphar.2016.05.039] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 05/17/2016] [Accepted: 05/30/2016] [Indexed: 01/10/2023]
Abstract
A large conductance potassium (BKCa) channel opener, NS1619 (1,3-dihydro-1- [2-hydroxy-5-(trifluoromethyl) phenyl]-5-(trifluoromethyl)-2H-benzimidazole-2-one), is well known for its protective effects against ischemia-reperfusion injury; however, the exact mode of its action remains unclear. The aim of this study was to characterize the effect of NS1619 on endothelial cells. The endothelial cell line EA.hy926, guinea pig hearts and submitochondrial particles isolated from the heart were used. In the isolated guinea pig hearts, which were perfused using the Langendorff technique, NS1619 caused a dose-dependent increase in coronary flow that was inhibited by L-NAME. In EA.hy926 cells, NS1619 also caused a dose-dependent increase in the intracellular calcium ion concentration [Ca(2+)]i, as measured using the FURA-2 fluorescent probe. Moreover, NS1619 decreased the oxygen consumption rate in EA.hy926 cells, as assessed using a Clark-type oxygen electrode. However, when NS1619 was applied in the presence of oligomycin, the oxygen consumption increased. NS1619 also decreased the mitochondrial membrane potential, as measured using a JC-1 fluorescent probe in the presence and absence of oligomycin. Additionally, the application of NS1619 to submitochondrial particles inhibited ATP synthase. In summary, NS1619 has pleiotropic actions on EA.hy926 cells and acts not only as an opener of the BKCa channel in EA.hy926 cells but also as an inhibitor of the respiratory chain component, sarcoplasmic reticulum ATPase, which leads to the release of Ca(2+) from the endoplasmic reticulum. Furthermore, NS1619 has the oligomycin-like property of inhibiting mitochondrial ATP synthase.
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Affiliation(s)
- Agnieszka Łukasiak
- Department of Biophysics, Warsaw University of Life Sciences SGGW, 159 Nowoursynowska St., 02-776 Warsaw, Poland.
| | - Agata Skup
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteura St., 02-093 Warsaw, Poland
| | - Stefan Chlopicki
- Jagiellonian Centre for Experimental Therapeutics (JCET), Jagiellonian University, 14 Bobrzynskiego St., 30-348 Krakow, Poland; Chair of Pharmacology, Jagiellonian University, Medical College, 16 Grzegorzecka, 31-531 Krakow, Poland
| | - Magdalena Łomnicka
- Chair of Pharmacology, Jagiellonian University, Medical College, 16 Grzegorzecka, 31-531 Krakow, Poland
| | - Patrycja Kaczara
- Jagiellonian Centre for Experimental Therapeutics (JCET), Jagiellonian University, 14 Bobrzynskiego St., 30-348 Krakow, Poland
| | - Bartosz Proniewski
- Jagiellonian Centre for Experimental Therapeutics (JCET), Jagiellonian University, 14 Bobrzynskiego St., 30-348 Krakow, Poland
| | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteura St., 02-093 Warsaw, Poland
| | - Antoni Wrzosek
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteura St., 02-093 Warsaw, Poland
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Calcium-Activated Potassium Channels: Potential Target for Cardiovascular Diseases. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 104:233-261. [PMID: 27038376 DOI: 10.1016/bs.apcsb.2015.11.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Ca(2+)-activated K(+) channels (KCa) are classified into three subtypes: big conductance (BKCa), intermediate conductance (IKCa), and small conductance (SKCa) KCa channels. The three types of KCa channels have distinct physiological or pathological functions in cardiovascular system. BKCa channels are mainly expressed in vascular smooth muscle cells (VSMCs) and inner mitochondrial membrane of cardiomyocytes, activation of BKCa channels in these locations results in vasodilation and cardioprotection against cardiac ischemia. IKCa channels are expressed in VSMCs, endothelial cells, and cardiac fibroblasts and involved in vascular smooth muscle proliferation, migration, vessel dilation, and cardiac fibrosis. SKCa channels are widely expressed in nervous and cardiovascular system, and activation of SKCa channels mainly contributes membrane hyperpolarization. In this chapter, we summarize the physiological and pathological roles of the three types of KCa channels in cardiovascular system and put forward the possibility of KCa channels as potential target for cardiovascular diseases.
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Dopico AM, Bukiya AN. Lipid regulation of BK channel function. Front Physiol 2014; 5:312. [PMID: 25202277 PMCID: PMC4141547 DOI: 10.3389/fphys.2014.00312] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 07/31/2014] [Indexed: 01/11/2023] Open
Abstract
This mini-review focuses on lipid modulation of BK (MaxiK, BKCa) current by a direct interaction between lipid and the BK subunits and/or their immediate lipid environment. Direct lipid-BK protein interactions have been proposed for fatty and epoxyeicosatrienoic acids, phosphoinositides and cholesterol, evidence for such action being less clear for other lipids. BK α (slo1) subunits are sufficient to support current perturbation by fatty and epoxyeicosatrienoic acids, glycerophospholipids and cholesterol, while distinct BK β subunits seem necessary for current modulation by most steroids. Subunit domains or amino acids that participate in lipid action have been identified in a few cases: hslo1 Y318, cerebral artery smooth muscle (cbv1) R334,K335,K336, cbv1 seven cytosolic CRAC domains, slo1 STREX and β1 T169,L172,L173 for docosahexaenoic acid, PIP2, cholesterol, sulfatides, and cholane steroids, respectively. Whether these protein motifs directly bind lipids or rather transmit the energy of lipid binding to other areas and trigger protein conformation change remains unresolved. The impact of direct lipid-BK interaction on physiology is briefly discussed.
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Affiliation(s)
- Alex M Dopico
- Department of Pharmacology, The University of Tennessee Health Science Center Memphis, TN, USA
| | - Anna N Bukiya
- Department of Pharmacology, The University of Tennessee Health Science Center Memphis, TN, USA
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Samarska IV, Bouma HR, Buikema H, Mungroop HE, Houwertjes MC, Absalom AR, Epema AH, Henning RH. S1P1 receptor modulation preserves vascular function in mesenteric and coronary arteries after CPB in the rat independent of depletion of lymphocytes. PLoS One 2014; 9:e97196. [PMID: 24819611 PMCID: PMC4018292 DOI: 10.1371/journal.pone.0097196] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 04/16/2014] [Indexed: 11/25/2022] Open
Abstract
Background Cardiopulmonary bypass (CPB) may induce systemic inflammation and vascular dysfunction. Sphingosine 1-phosphate (S1P) modulates various vascular and immune responses. Here we explored whether agonists of the S1P receptors, FTY720 and SEW2871 improve vascular reactivity after CPB in the rat. Methods Experiments were done in male Wistar rats (total n = 127). Anesthesia was induced by isoflurane (2.5–3%) and maintained by fentanyl and midazolam during CPB. After catheterization of the left femoral artery, carotid artery and the right atrium, normothermic extracorporeal circulation was instituted for 60 minutes. In the first part of the study animals were euthanized after either 1 hour, 1 day, 2 or 5 days of the recovery period. In second part of the study animals were euthanized after 1 day of postoperative period. We evaluated the contractile response to phenylephrine (mesenteric arteries) or to serotonin (coronary artery) and vasodilatory response to acethylcholine (both arteries). Results Contractile responses to phenylephrine were reduced at 1 day recovery after CPB and Sham as compared to healthy control animals (Emax, mN: 7.9±1.9, 6.5±1.5, and 11.3±1.3, respectively). Mainly FTY720, but not SEW2871, caused lymphopenia in both Sham and CPB groups. In coronary and mesenteric arteries, both FTY720 and SEW2871 normalized serotonin and phenylephrine-mediated vascular reactivity after CPB (p<0.05) and FTY720 increased relaxation to acetylcholine as compared with untreated rats that underwent CPB. Conclusion Pretreatment with FTY720 or SEW2871 preserves vascular function in mesenteric and coronary artery after CPB. Therefore, pharmacological activation of S1P1 receptors may provide a promising therapeutic intervention to prevent CPB-related vascular dysfunction in patients.
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Affiliation(s)
- Iryna V. Samarska
- Department of Anesthesiology, University of Groningen, University Medical Center Groningen, The Netherlands
- * E-mail:
| | - Hjalmar R. Bouma
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Hendrik Buikema
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Hubert E. Mungroop
- Department of Anesthesiology, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Martin C. Houwertjes
- Department of Anesthesiology, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Anthony R. Absalom
- Department of Anesthesiology, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Anne H. Epema
- Department of Anesthesiology, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Robert H. Henning
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, The Netherlands
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Zhou L, Zhang YJ, Gao LJ, Ye Y, Qi JH, Qi Z. Structure–activity relationship of Baifuzi-cerebrosides on BKCa channel activation. Eur J Med Chem 2014; 75:301-7. [DOI: 10.1016/j.ejmech.2014.01.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 01/03/2014] [Accepted: 01/04/2014] [Indexed: 11/29/2022]
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Chan JP, Hu Z, Sieburth D. Recruitment of sphingosine kinase to presynaptic terminals by a conserved muscarinic signaling pathway promotes neurotransmitter release. Genes Dev 2012; 26:1070-85. [PMID: 22588719 DOI: 10.1101/gad.188003.112] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Sphingolipids are potent lipid second messengers that regulate cell differentiation, migration, survival, and secretion, and alterations in sphingolipid signaling have been implicated in a variety of diseases. However, how sphingolipid levels are regulated, particularly in the nervous system, remains poorly understood. Here, we show that the generation of sphingosine-1-phosphate by sphingosine kinase (SphK) promotes neurotransmitter release. Electrophysiological, imaging, and behavioral analyses of Caenorhabditis elegans mutants lacking sphingosine kinase sphk-1 indicate that neuronal development is normal, but there is a significant defect in neurotransmitter release from neuromuscular junctions. SPHK-1 localizes to discrete, nonvesicular regions within presynaptic terminals, and this localization is critical for synaptic function. Muscarinic agonists cause a rapid increase in presynaptic SPHK-1 abundance, whereas reduction of endogenous acetylcholine production results in a rapid decrease in presynaptic SPHK-1 abundance. Muscarinic regulation of presynaptic SPHK-1 abundance is mediated by a conserved presynaptic signaling pathway composed of the muscarinic acetylcholine receptor GAR-3, the heterotrimeric G protein Gαq, and its effector, Trio RhoGEF. SPHK-1 activity is required for the effects of muscarinic signaling on synaptic transmission. This study shows that SPHK-1 promotes neurotransmitter release in vivo and identifies a novel muscarinic pathway that regulates SphK abundance at presynaptic terminals.
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Affiliation(s)
- Jason P Chan
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California 90033, USA
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13
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The GPR55 agonist lysophosphatidylinositol directly activates intermediate-conductance Ca2+ -activated K+ channels. Pflugers Arch 2011; 462:245-55. [PMID: 21603896 PMCID: PMC3132407 DOI: 10.1007/s00424-011-0977-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 04/27/2011] [Accepted: 05/10/2011] [Indexed: 12/16/2022]
Abstract
Lysophosphatidylinositol (LPI) was recently shown to act both as an extracellular mediator binding to G protein-coupled receptor 55 (GPR55) and as an intracellular messenger directly affecting a number of ion channels including large-conductance Ca(2+) and voltage-gated potassium (BK(Ca)) channels. Here, we explored the effect of LPI on intermediate-conductance Ca(2+)-activated K(+) (IK(Ca)) channels using excised inside-out patches from endothelial cells. The functional expression of IK(Ca) was confirmed by the charybdotoxin- and TRAM-34-sensitive hyperpolarization to histamine and ATP. Moreover, the presence of single IK(Ca) channels with a slope conductance of 39 pS in symmetric K(+) gradient was directly confirmed in inside-out patches. When cytosolically applied in the range of concentrations of 0.3-10 μM, which are well below the herein determined critical micelle concentration of approximately 30 μM, LPI potentiated the IK(Ca) single-channel activity in a concentration-dependent manner, while single-channel current amplitude was not affected. In the whole-cell configuration, LPI in the pipette was found to facilitate membrane hyperpolarization in response to low (0.5 μM) histamine concentrations in a TRAM-34-sensitive manner. These results demonstrate a so far not-described receptor-independent effect of LPI on the IK(Ca) single-channel activity of endothelial cells, thus, highlighting LPI as a potent intracellular messenger capable of modulating electrical responses in the vasculature.
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Xu H, Qi J, Wang G, Deng H, Qi Z. The effect of single cerebroside compounds on activation of BKCa channels. Mol Membr Biol 2010; 28:145-54. [PMID: 21190430 DOI: 10.3109/09687688.2010.538731] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We have previously shown that a mixture of cerebrosides obtained from dried tubers of herb Typhonium giganteum Engl. plays a neuroprotective role in the ischemic brain through its effect on activation of BK(Ca) channels. It is very curious to know whether a single pure cerebroside compound could activate the BK(Ca) channel as well. This study explored the possible effects of pure cerebroside compounds, termitomycesphins A and B, on the BK(Ca) channel activation. Both termitomycesphins A and B activated the BK(Ca) channels at micromole concentration without significant difference. Termitomycesphin A increased the single channel open probability of the BK(Ca) channels in a dose-dependent manner without modifying the single channel conductance. Termitomycesphin A activated BK(Ca) channel more efficiently when it was applied to the cytoplasmic face of the membrane, suggesting that binding site for termitomycesphin A is located at the cytoplasmic side. Termitomycesphin A shifted the voltage-dependent activation curve to less positive membrane potentials and the Ca(2+)-dependent activation curve of the channel upwards, suggesting that termitomycesphin A could activate the channels even without intracellular free Ca(2+). Furthermore, STREX-deleted BK(Ca) channels were completely insensitive to termitomycesphin A, indicating that STREX domain is required for the activation of the BK(Ca) channel. These data provide evidence that termitomycesphins are potent in stimulating the activity of the BK(Ca) channels. As BK(Ca) channels are associated with pathology of many diseases, termitomycesphins might be used as therapeutic agents for treating these diseases through its regulatory effect on the BK(Ca) channels.
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Affiliation(s)
- Huina Xu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
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15
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The GPR55 agonist lysophosphatidylinositol acts as an intracellular messenger and bidirectionally modulates Ca2+ -activated large-conductance K+ channels in endothelial cells. Pflugers Arch 2010; 461:177-89. [PMID: 21072666 PMCID: PMC3014879 DOI: 10.1007/s00424-010-0898-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 10/08/2010] [Accepted: 10/25/2010] [Indexed: 02/03/2023]
Abstract
Lysophospholipids are known to serve as intra- and extracellular messengers affecting many physiological processes. Lysophosphatidylinositol (LPI), which is produced in endothelial cells, acts as an endogenous agonist of the orphan receptor, G protein-coupled receptor 55 (GPR55). Stimulation of GPR55 by LPI evokes an intracellular Ca2+ rise in several cell types including endothelial cells. In this study, we investigated additional direct, receptor-independent effects of LPI on endothelial large-conductance Ca2+ and voltage-gated potassium (BKCa) channels. Electrophysiological experiments in the inside-out configuration revealed that LPI directly affects the BKCa channel gating properties. This effect of LPI strictly depended on the presence of Ca2+ and was concentration-dependent, reversible, and dual in nature. The modulating effects of LPI on endothelial BKCa channels correlated with their initial open probability (Po): stimulation at low Po (<0.3) and inhibition at high Po levels (>0.3). In the whole-cell configuration, LPI in the pipette facilitated membrane hyperpolarization in response to low (0.1–2 μM) histamine concentrations. In contrast, LPI counteracted membrane hyperpolarization in response to supramaximal cell stimulation with histamine. These results highlight a novel receptor-independent and direct bidirectional modulation of BKCa channels by LPI on endothelial cells. We conclude that LPI via this mechanism serves as an important modulator of endothelial electrical responses to cell stimulation.
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Vang A, Mazer J, Casserly B, Choudhary G. Activation of endothelial BKCa channels causes pulmonary vasodilation. Vascul Pharmacol 2010; 53:122-9. [PMID: 20470901 DOI: 10.1016/j.vph.2010.05.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 04/28/2010] [Accepted: 05/06/2010] [Indexed: 12/21/2022]
Abstract
BACKGROUND Large-conductance Ca(2+)-activated K(+) (BK(Ca)) channels cause hyperpolarization and can regulate vascular tone. In this study, we evaluated the effect of endothelial BK(Ca) activation on pulmonary vascular tone. METHODS The presence of BK(Ca) channels in lung microvascular endothelial cells (LMVEC) and rat lung tissue was confirmed by RT-PCR, immunoblotting and immunohistochemistry. Isolated pulmonary artery (PA) rings and isolated ventilated-perfused rat lungs were used to assay the effects of BK(Ca) channel activation on endothelium-dependent vasodilation. RESULTS Immunoblotting and RT-PCR revealed the presence of BK(Ca) channel alpha- and beta(4)-subunits in LMVEC. Immunohistochemical staining showed BK(Ca) channel alpha-subunit expression in vascular endothelium in rat lungs. In arterial ring studies, BK(Ca) channel activation by NS1619 enhanced endothelium-dependent vasodilation that was attenuated by tetraethylammonium and iberiotoxin. In addition, activation of BK(Ca) channels by C-type natriuretic peptide caused endothelial-dependent vasodilation that was blocked by iberiotoxin, L-NAME, and lanthanum. Furthermore, BK(Ca) activation by NS1619 caused a dose-dependent reduction in PA pressures that was attenuated by L-NAME. In vitro, BK(Ca) channel activation in LMVEC caused hyperpolarization and increased NO production. CONCLUSIONS Pulmonary endothelium expresses BK(Ca) channels. Activation of endothelial BK(Ca) channels causes hyperpolarization and NO mediated endothelium-dependent vasodilation in micro- and macrovasculature in the lung.
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Affiliation(s)
- Alexander Vang
- Vascular Research Laboratory, Providence VA Medical Center, Providence, RI 02908, USA
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Spijkers LJA, Alewijnse AE, Peters SLM. Sphingolipids and the orchestration of endothelium-derived vasoactive factors: when endothelial function demands greasing. Mol Cells 2010; 29:105-11. [PMID: 20127284 DOI: 10.1007/s10059-010-0042-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 01/08/2010] [Indexed: 02/02/2023] Open
Abstract
Vasomotor tone is regulated by a complex interplay of a variety of extrinsic neurohumoral and intrinsic factors. It is the endothelium that has a major influence on smooth muscle cell tone via the release of intrinsic vasoactive factors and is therefore an important regulator of vasomotor tone. Sphingolipids are an emerging class of lipid mediators with important physiological properties. In the last two decades it has not only become increasingly clear that sphingolipid signaling plays a pivotal role in immune function, but also its role in the vascular system is now becoming more recognized. In this mini-review we will highlight the possible cross-talk between sphingolipids and intrinsic vasoactive factors released by the endothelium. Via this cross-talk sphingolipids can orchestrate vasomotor tone and may therefore also be involved in the pathophysiology of disease states associated with endothelial dysfunction.
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Affiliation(s)
- Léon J A Spijkers
- Department Pharmacology and Pharmacotherapy, Academic Medical Center, Amsterdam, The Netherlands
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Szewczyk A, Kajma A, Malinska D, Wrzosek A, Bednarczyk P, Zabłocka B, Dołowy K. Pharmacology of mitochondrial potassium channels: dark side of the field. FEBS Lett 2010; 584:2063-9. [PMID: 20178786 DOI: 10.1016/j.febslet.2010.02.048] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 01/25/2010] [Accepted: 02/15/2010] [Indexed: 11/25/2022]
Abstract
Mitochondrial potassium channels play an important role in cytoprotection. Potassium channels in the inner mitochondrial membrane are modulated by inhibitors and activators (potassium channel openers) previously described for plasma membrane potassium channels. The majority of mitochondrial potassium channel modulators exhibit a broad spectrum of off-target effects. These include uncoupling properties, inhibition of the respiratory chain and effects on cellular calcium homeostasis. Therefore, the rational application of channel inhibitors or activators is crucial to understanding the cellular consequences of mitochondrial channel inhibition or activation. Moreover, understanding their side-effects should facilitate the design of a specific mitochondrial channel opener with cytoprotective properties. In this review, we discuss the complex interactions of potassium channel inhibitors and activators with cellular structures.
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Affiliation(s)
- Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland.
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Kim MY, Liang GH, Kim JA, Choi SS, Choi S, Suh SH. Oxidized Low-density Lipoprotein- and Lysophosphatidylcholine-induced Ca Mobilization in Human Endothelial Cells. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2009; 13:27-32. [PMID: 19885023 DOI: 10.4196/kjpp.2009.13.1.27] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The effects of oxidized low-density lipoprotein (OxLDL) and its major lipid constituent lysophosphatidylcholine (LPC) on Ca(2+) entry were investigated in cultured human umbilical endothelial cells (HUVECs) using fura-2 fluorescence and patch-clamp methods. OxLDL or LPC increased intracellular Ca(2+) concentration ([Ca(2+)](i)), and the increase of [Ca(2+)](i) by OxLDL or by LPC was inhibited by La(3+) or heparin. LPC failed to increase [Ca(2+)](i) in the presence of an antioxidant tempol. In addition, store-operated Ca(2+) entry (SOC), which was evoked by intracellular Ca(2+) store depletion in Ca(2+)-free solution using the sarcoplasmic reticulum Ca(2+) pump blocker, 2, 5-di-t-butyl-1, 4-benzohydroquinone (BHQ), was further enhanced by OxLDL or by LPC. Increased SOC by OxLDL or by LPC was inhibited by U73122. In voltage-clamped cells, OxLDL or LPC increased [Ca(2+)](i) and simultaneously activated non-selective cation (NSC) currents. LPC-induced NSC currents were inhibited by 2-APB, La(3+) or U73122, and NSC currents were not activated by LPC in the presence of tempol. Furthermore, in voltage-clamped HUVECs, OxLDL enhanced SOC and evoked outward currents simultaneously. Clamping intracellular Ca(2+) to 1 microM activated large-conductance Ca(2+)-activated K(+) (BK(Ca)) current spontaneously, and this activated BK(Ca) current was further enhanced by OxLDL or by LPC. From these results, we concluded that OxLDL or its main component LPC activates Ca(2+)-permeable Ca(2+)-activated NSC current and BK(Ca) current simultaneously, thereby increasing SOC.
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Affiliation(s)
- Moon Young Kim
- Department of Physiology and Medical Research Institute, School of Medicine, Ewha Womans University, Seoul 158-710, Korea
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20
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Wrzosek A, Łukasiak A, Gwóźdź P, Malińska D, Kozlovski VI, Szewczyk A, Chlopicki S, Dołowy K. Large-conductance K+ channel opener CGS7184 as a regulator of endothelial cell function. Eur J Pharmacol 2009; 602:105-11. [DOI: 10.1016/j.ejphar.2008.10.066] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 09/19/2008] [Accepted: 10/29/2008] [Indexed: 01/08/2023]
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21
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Olivera A. Unraveling the complexities of sphingosine-1-phosphate function: the mast cell model. Prostaglandins Other Lipid Mediat 2008; 86:1-11. [PMID: 18403224 DOI: 10.1016/j.prostaglandins.2008.02.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Accepted: 02/26/2008] [Indexed: 11/16/2022]
Abstract
Sphingosine-1-phosphate (S1P) is a lipid mediator involved in diverse biological processes, from vascular and neural development to the regulation of lymphocyte trafficking. Many of its functions are regulated by five widely expressed S1P G-protein-coupled receptors (S1P(1-5)). S1P is produced mostly intracellularly, thus, much of its potential as an autocrine and paracrine mediator depends on how, when, and where it is generated or secreted out of the cells. However, S1P can also have intracellular activity independent of its receptors, adding to the complexity of S1P function. The mast cell, a major effector cell during an allergic response, has proven instrumental towards understanding the complex regulation and function of S1P. Antigen (Ag) engagement of the IgE receptor in mast cells stimulates sphingosine kinases, which generate S1P and are involved in the activation of calcium fluxes critical for mast cell responses. In addition, mast cells secrete considerable amounts of S1P upon activation, thus affecting the surrounding tissues and recruiting inflammatory cells. Export of S1P is also involved in the autocrine transactivation of S1P receptors present in mast cells. The in vivo response of mast cells, however, is not strictly dependent on their ability to generate S1P, but they are also affected by changes in S1P in the environment previous to Ag challenge. This review will discuss the recent advances towards understanding the intricacies of S1P generation, secretion and regulation in mast cells. In addition, how S1P receptors are activated and their involvement in mast cell functions will also be covered, including new insights on the role of S1P in the mast cell-mediated allergic response of systemic anaphylaxis.
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Affiliation(s)
- Ana Olivera
- Laboratory of Immune Cell Signaling, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, 9 Memorial Dr, Bldg 9, room# 1W122, Bethesda, MD 20892, USA.
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Pan CY, Wu AZ, Chen YT. Lysophospholipids regulate excitability and exocytosis in cultured bovine chromaffin cells. J Neurochem 2007; 102:944-56. [PMID: 17630986 DOI: 10.1111/j.1471-4159.2007.04584.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Bioactive lysophospholipids (LPLs) are released by blood cells and can modulate many cellular activities such as angiogenesis and cell survival. In this study, the effects of sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA) on excitability and exocytosis in bovine chromaffin cells were investigated using the whole-cell configuration of the patch-clamp. Voltage-gated Ca(2+) current was inhibited by S1P and LPA pre-treatment in a concentration-dependent manner with IC(50)s of 0.46 and 0.79 mumol/L, respectively. Inhibition was mostly reversible upon washout and prevented by suramin, an inhibitor of G-protein signaling. Na(+) current was inhibited by S1P, but not by LPA. However, recovery of Na(+) channels from inactivation was slowed by both LPLs. The outward K(+) current was also significantly reduced by both LPLs. Chromaffin cells fired repetitive action potentials in response to minimal injections of depolarizing current. Repetitive activity was dramatically reduced by LPLs. Consistent with the reduction in Ca(2+) current, exocytosis elicited by a train of depolarizations and the ensuing endocytosis were both inhibited by LPL pre-treatments. These data demonstrate the interaction between immune and endocrine systems mediated by the inhibitory effects of LPLs on the excitability of adrenal chromaffin cells.
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Affiliation(s)
- Chien-Yuan Pan
- Institute of Zoology, National Taiwan University, Taipei, Taiwan.
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Watterson KR, Berg KM, Kapitonov D, Payne SG, Miner AS, Bittman R, Milstien S, Ratz PH, Spiegel S. Sphingosine‐1‐phosphate and the immunosuppressant, FTY720‐phosphate, regulate detrusor muscle tone. FASEB J 2007; 21:2818-28. [PMID: 17449719 DOI: 10.1096/fj.06-7326com] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Overactive bladder syndrome (OBS) results from disturbances of bladder function. Bladder smooth muscle (detrusor) exhibits spontaneous rhythmic activity (tone) independent of neurogenic control, which is enhanced in patients with OBS. We have now uncovered a prominent role for the bioactive sphingolipid metabolite, sphingosine-1-phosphate (S1P), in regulating rabbit detrusor smooth muscle tone and contraction. S1P-induced contraction of detrusor muscle was dependent on stretch and intracellular calcium. Although detrusor expresses the S1P receptors S1P1 and S1P2, only S1P2 appeared to be involved in S1P-induced contraction, since SEW2871 (S1P1 agonist) and dihydro-S1P (potent agonist for all S1P receptors except S1P2) were poor contractile agents. In agreement, the S1P2 antagonist JTE013 inhibited S1P-induced contraction. The fast, transient muscle contraction (phasic) mediated by S1P was dependent on phospholipase C (PLC) whereas the slower, sustained contraction (tonic) was not. Surprisingly, the immunosuppressant FTY720-phosphate, an agonist for all S1P receptors except S1P2, had distinct contractile properties and also induced slow, sustained contraction. Thus, FTY720-phosphate and/or S1P may regulate calcium channels in an S1P receptor-independent manner. Collectively, our results demonstrate that S1P may regulate detrusor smooth muscle tone and suggest that dysregulation of complex S1P signaling might contribute to OBS.
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Affiliation(s)
- Kenneth R Watterson
- Department of Biochemistry and Molecular Biology, VCU School of Medicine, 1101 E. Marshall St., Richmond, VA 23298, USA
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Shin JH, Choi GS, Kang WH, Myung KB. Sphingosine 1-phosphate triggers apoptotic signal for B16 melanoma cells via ERK and caspase activation. J Korean Med Sci 2007; 22:298-304. [PMID: 17449940 PMCID: PMC2693598 DOI: 10.3346/jkms.2007.22.2.298] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Accepted: 09/13/2006] [Indexed: 12/18/2022] Open
Abstract
The bioactive sphingolipid metabolite sphingosine 1-phosphate (S1P), recently was reported to induce apoptosis of some cancer cells and neurons, although it generally known to exert mitogenic and antiapoptotic effects. In this study, we investigated the effects of S1P on the cell growth, melanogenesis, and apoptosis of cultured B16 mouse melanoma cells. In results, S1P was found to induce apoptosis in B16 melanoma cells in a dose- and time-dependent manner, but exerted minimal effects on melanogenesis. Although receptors of sphingosine 1-phosphate (endothelial differentiation gene 1 [Edg]/S1P(1), Edg5/S1P(2), Edg3/S1P(3)) were expressed in B16 melanoma cells, they were shown not to be associated with S1P-induced apoptosis. In addition, pertussis toxin did not block the apoptotic effects of S1P on B16 melanoma cells. S1P induced caspase-3 activation and the extracellular signal-regulated kinase (ERK) activation. Interestingly, the ERK pathway inhibitor, UO126, reversed the apoptotic effects of S1P on B16 melanoma cells. These results suggest that S1P induced apoptosis of B16 melanoma cells via an Edg receptor-independent, pertussis toxin-insensitive pathway, and appears to be associated with the ERK and caspase-3 activation.
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Affiliation(s)
- Jeong-Hyun Shin
- Department of Dermatology, School of Medicine, Inha University, Incheon, Korea
| | - Gwang-Seong Choi
- Department of Dermatology, School of Medicine, Inha University, Incheon, Korea
| | - Won-Hyung Kang
- Department of Dermatology, School of Medicine, Ajou University, Suwon, Korea
| | - Ki-Bum Myung
- Department of Dermatology, School of Medicine, Ewha Womans University, Seoul, Korea
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25
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Hemmings DG. Signal transduction underlying the vascular effects of sphingosine 1-phosphate and sphingosylphosphorylcholine. Naunyn Schmiedebergs Arch Pharmacol 2006; 373:18-29. [PMID: 16570136 DOI: 10.1007/s00210-006-0046-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Two related lysosphingolipids, sphingosine 1-phosphate (S1P) and sphingosylphosphorylcholine (SPC) mediate diverse cellular responses through signals transduced by either activation of G-protein coupled receptors or possibly by acting intracellularly. Vascular responses to S1P and SPC measured both in vivo and in dissected vessels show predominantly vasoconstriction with some evidence for vasodilation. Although stimulation with S1P or SPC generally leads to similar vascular responses, the signalling pathways stimulated to produce these responses are often distinct. Nevertheless, mobilization of Ca2+ from intracellular stores and influx of extracellular Ca2+, which both increase [Ca2+]i, occur in response to S1P and SPC. Both mobilization of Ca2+ from intracellular stores and influx of extracellular Ca2+ occur in response to S1P and SPC. As well, both S1P and SPC induce Ca2+-sensitization in vascular smooth muscle which is mediated through Rho kinase activation. In the endothelium, S1P and SPC stimulate the production of the vasodilator, nitric oxide through activation of endothelial nitric oxide synthase. This activation occurs through phosphorylation by Akt and through binding of Ca2+-calmodulin upon increased [Ca2+]i. These lysosphingolipids also activate cyclooxygenase-2 which produces prostaglandins with both vasoconstrictor and vasodilator properties. A balance between the signals inducing vasodilation versus the signals inducing vasoconstriction will determine the vascular outcome. Thus, perturbations in S1P and SPC concentrations, relative expression of receptors or downstream signalling pathways may provide a mechanism for pathophysiological conditions such as hypertension. Given this background, recent studies examining a potential role for S1P and SPC in hypertension and vascular dysfunction in aging are discussed.
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Affiliation(s)
- Denise G Hemmings
- Department Obstetrics and Gynecology, Perinatal Research Centre, University of Alberta, 227 Heritage Medical Research Center, T6G 2S2, Edmonton, Alberta, Canada.
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