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Kume H, Harigane R, Rikimaru M. Involvement of Lysophospholipids in Pulmonary Vascular Functions and Diseases. Biomedicines 2024; 12:124. [PMID: 38255229 PMCID: PMC10813361 DOI: 10.3390/biomedicines12010124] [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: 10/31/2023] [Revised: 12/26/2023] [Accepted: 01/03/2024] [Indexed: 01/24/2024] Open
Abstract
Extracellular lysophospholipids (lysophosphatidic acid, lysophosphatidylcholine, sphingosine 1-phosphate, etc.), which are synthesized from phospholipids in the cell membrane, act as lipid mediators, and mediate various cellular responses in constituent cells in the respiratory system, such as contraction, proliferation, migration, and cytoskeletal organization. In addition to these effects, the expression of the adhesion molecules is enhanced by these extracellular lysophospholipids in pulmonary endothelial cells. These effects are exerted via specific G protein-coupled receptors. Rho, Ras, and phospholipase C (PLC) have been proven to be their signaling pathways, related to Ca2+ signaling due to Ca2+ dynamics and Ca2+ sensitization. Therefore, lysophospholipids probably induce pulmonary vascular remodeling through phenotype changes in smooth muscle cells, endothelial cells, and fibroblasts, likely resulting in acute respiratory distress syndrome due to vascular leak, pulmonary hypertension, and pulmonary fibrosis. Moreover, lysophospholipids induce the recruitment of inflammatory cells to the lungs via the enhancement of adhesion molecules in endothelial cells, potentially leading to the development of asthma. These results demonstrate that lysophospholipids may be novel therapeutic targets not only for injury, fibrosis, and hypertension in the lung, but also for asthma. In this review, we discuss the mechanisms of the effects of lysophospholipids on the respiratory system, and the possibility of precision medicine targeting lysophospholipids as treatable traits of these diseases.
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Affiliation(s)
- Hiroaki Kume
- Department of Infectious Diseases and Respiratory Medicine, Fukushima Medical University Aizu Medical Center, 21-2 Maeda, Tanisawa, Kawahigashi, Aizuwakamatsu City 969-3492, Fukushima, Japan; (R.H.); (M.R.)
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Abdelwahid MS, Ohsawa K, Uwamizu A, Kano K, Aoki J, Doi T. Synthesis and Biological Evaluation of Lysophosphatidic Acid Analogues Using Conformational Restriction and Bioisosteric Replacement Strategies. ACS OMEGA 2023; 8:49278-49288. [PMID: 38162765 PMCID: PMC10753746 DOI: 10.1021/acsomega.3c07668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/08/2023] [Accepted: 11/13/2023] [Indexed: 01/03/2024]
Abstract
Lysophosphatidic acid (LPA) is a key player in many physiological and pathophysiological processes. The biological activities of LPA are mediated through interactions with-at least-six subtypes of G-protein-coupled receptors (GPCRs) named LPA1-6. Developing a pharmacological tool molecule that activates LPA subtype receptors selectively will allow a better understanding of their specific physiological roles. Here, we designed and synthesized conformationally restricted 25 1-oleoyl LPA analogues MZN-001 to MZN-025 by incorporating its glycerol linker into dihydropyran, tetrahydropyran, and pyrrolidine rings and variating the lipophilic chain. The agonistic activities of these compounds were evaluated using the TGFα shedding assay. Overall, the synthesized analogues exhibited significantly reduced agonistic activities toward LPA1, LPA2, and LPA6, while demonstrating potent activities toward LPA3, LPA4, and LPA5 compared to the parent LPA. Specifically, MZN-010 showed more than 10 times greater potency (EC50 = 4.9 nM) than the standard 1-oleoyl LPA (EC50 = 78 nM) toward LPA5 while exhibiting significantly lower activity on LPA1, LPA2, and LPA6 and comparable potency toward LPA3 and LPA4. Based on the MZN-010 scaffold, we synthesized additional analogues with improved selectivity and potency toward LPA5. Compound MZN-021, which contains a saturated lipophilic chain, exhibited 50 times more potent activity (EC50 = 1.2 nM) than the natural LPA against LPA5 with over a 45-fold higher selectivity when compared to those of other LPA receptors. Thus, MZN-021 was found to be a potent and selective LPA5 agonist. The findings of this study could contribute to broadening the current knowledge about the stereochemical and three-dimensional arrangement of LPA pharmacophore components inside LPA receptors and paving the way toward synthesizing other subtype-selective pharmacological probes.
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Affiliation(s)
- Mazin
A. S. Abdelwahid
- Graduate
School of Pharmaceutical Sciences, Tohoku
University, 6-3 Aza-aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Kosuke Ohsawa
- Graduate
School of Pharmaceutical Sciences, Tohoku
University, 6-3 Aza-aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Akiharu Uwamizu
- Graduate
School of Pharmaceutical Sciences, The University
of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kuniyuki Kano
- Graduate
School of Pharmaceutical Sciences, The University
of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Junken Aoki
- Graduate
School of Pharmaceutical Sciences, The University
of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takayuki Doi
- Graduate
School of Pharmaceutical Sciences, Tohoku
University, 6-3 Aza-aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
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Effects of lysophosphatidic acid on sling and clasp fibers of the human lower esophageal sphincter. TURKISH JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY 2022; 30:404-409. [PMID: 36303683 PMCID: PMC9580277 DOI: 10.5606/tgkdc.dergisi.2022.22084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 08/05/2021] [Indexed: 11/21/2022]
Abstract
Background
This study aims to explore the role of lysophosphatidic acid receptors in the regulation mechanisms of contraction and relaxation of human lower esophageal sphincter.
Methods
Between July 2015 and March 2016, muscle strips were collected from a total of 30 patients (19 males, 11 females; mean age: 62±9.9 years; range, 52 to 68 years) who underwent an esophagectomy for mid-third esophageal carcinomas. The specimens were maintained in oxygenated Krebs solution. Muscle tension measurement technique in vitro was used to examine the effects of non-selective lysophosphatidic acid receptors agonists and antagonists, as well as selective lysophosphatidic acid receptors agonists on the clasp and sling fibers of human lower esophageal sphincter.
Results
The non-selective dopamine receptor agonist lysophosphatidic acid induced the contraction of the clasp and sling fibers of the human lower esophageal sphincter. The response induced by nonselective lysophosphatidic acid receptor agonist was inhibited completely by non-selective lysophosphatidic acid receptor antagonist. The selective lysophosphatidic acid 1 and 2 receptor agonist and the selective lysophosphatidic acid 3 receptor agonist induced a concentration-dependent contractile response of the clasp and sling fibers of the human lower esophageal sphincter. There was no significant difference in contraction rates between the clasp and sling fibers (p>0.05).
Conclusion
This study indicates that lysophosphatidic acid regulates the lower esophageal sphincter is through its receptor; the lysophosphatidic acid receptors may be involved in the contractile response of the human lower esophageal sphincter.
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Lysophosphatidic acid (LPA) as a modulator of plasma membrane Ca 2+-ATPase from basolateral membranes of kidney proximal tubules. J Physiol Biochem 2021; 77:321-329. [PMID: 33704695 DOI: 10.1007/s13105-021-00800-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 02/15/2021] [Indexed: 01/10/2023]
Abstract
Lysophosphatidic acid (LPA) acts through the activation of G protein-coupled receptors, in a Ca2+-dependent manner. We show the effects of LPA on the plasma membrane Ca2+-ATPase (PMCA) from kidney proximal tubule cells. The Ca2+-ATPase activity was inhibited by nanomolar concentrations of LPA, with maximal inhibition (~50%) obtained with 20 nM LPA. This inhibitory action on PMCA activity was blocked by Ki16425, an antagonist for LPA receptors, indicating that this lipid acts via LPA1 and/or LPA3 receptor. This effect is PKC-dependent, since it is abolished by calphostin C and U73122, PKC, and PLC inhibitors, respectively. Furthermore, the addition of 10-8 M PMA, a well-known PKC activator, mimicked PMCA modulation by LPA. We also demonstrated that the PKC activation leads to an increase in PMCA phosphorylation. These results indicate that LPA triggers LPA1 and/or LPA3 receptors at the BLM, inducing PKC-dependent phosphorylation with further inhibition of PMCA. Thus, LPA is part of the regulatory lipid network present at the BLM and plays an important role in the regulation of intracellular Ca2+ concentration that may result in significant physiological alterations in other Ca2+-dependent events ascribed to the renal tissue.
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Liu Y, Chen F, Ji L, Zhang L, Xu YJ, Dhalla NS. Role of lysophosphatidic acid in vascular smooth muscle cell proliferation. Can J Physiol Pharmacol 2019; 98:103-110. [PMID: 31369714 DOI: 10.1139/cjpp-2019-0264] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Lysophosphatidic acid (LPA) is an important lipid molecule for signal transduction in cell proliferation. Although the effects of LPA on vascular smooth muscle (VSM) cell growth have been reported previously, the underlying mechanisms of its action are not fully understood. The present study was undertaken to investigate the effects of some inhibitors of different protein kinases and other molecular targets on LPA-induced DNA synthesis as well as gene expression in the aortic VSM cells. The DNA synthesis was studied by the [3H]thymidine incorporation method and the gene expression was investigated by the real-time PCR technique. It was observed that the LPA-induced DNA synthesis was attenuated by inhibitors of protein kinase C (PKC) (staurosporine, calphostin C, and bisindolylmaleimide), phosphoinositide 3-kinase (PI3K) (wortmannin and LY294002), and ribosomal p70S6 kinase (p70S6K) (rapamycin). The inhibitors of guanine protein coupled receptors (GPCR) (pertussis toxin), phospholipase C (PLC) (U73122 and D609), and sodium-hydrogen exchanger (NHE) (amiloride and dimethyl amiloride) were also shown to depress the LPA-induced DNA synthesis. Furthermore, gene expressions for PLC β1 isoform, PKC δ and ε isoforms, casein kinase II β isoform, and endothelin-1A receptors were elevated by LPA. These results suggest that the LPA-induced proliferation of VSM cells is mediated through the activation of GPCR and multiple protein kinases as well as gene expressions of some of their specific isoforms.
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Affiliation(s)
- Yingying Liu
- Department of Nephrology, China-Japan Union Hospital of Jilin University, Changchun, Jilin, China, 130033
| | - Feng Chen
- Department of Dermatology, China-Japan Union Hospital of Jilin University, Changchun, Jilin, China, 130033
| | - Lei Ji
- Department of Cardiology, China-Japan Union Hospital of Jilin University, Changchun, Jilin, China, 130033
| | - Lingrui Zhang
- Department of Gastroenterology, China-Japan Union Hospital of Jilin University, Changchun, Jilin, China, 130033
| | - Yan-Jun Xu
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Center, and Department of Physiology and Pathophysiology, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R2H 2A6, Canada
| | - Naranjan S Dhalla
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Center, and Department of Physiology and Pathophysiology, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R2H 2A6, Canada
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Zhang Y, Zhang JD, Zhu MQ, Zhang M, Xu YJ, Cui L, Dhalla NS. Effect of lysophosphatidylglycerol on intracellular free Ca 2+ concentration in A10 vascular smooth muscle cells. Can J Physiol Pharmacol 2017; 95:1283-1288. [PMID: 28727921 DOI: 10.1139/cjpp-2017-0127] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Although plasma levels of lysophosphatidylglycerol (LPG) are increased in hypertension, its role in the pathogenesis of vascular defects is not clear. In view of the importance of Ca2+ overload in causing vascular smooth muscle (VSM) dysfunction, the action of LPG on [Ca2+]i in cultured A10 VSM cell line was examined by using Fura 2-AM acetoxymethyl ester technique. LPG was found to induce a concentration-dependent increase in [Ca2+]i in VSM cells. This change was dependent both on the extracellular and intracellular Ca2+ sources, as it was reduced by 30% by EGTA, an extracellular Ca2+ chelator, and 70% by thapsigargin, a sarcoplasmic reticulum (SR) Ca2+-pump inhibitor. However the increase in [Ca2+]i due to LPG was not altered by caffeine or ryanodine, which affect Ca2+-release through the ryanodine receptors in the SR. On the other hand, LPG-induced change in [Ca2+]i was suppressed by 2-nitro-4-carboxyphenyl N,N-diphenylcarbamate, a phospholipase C (PLC) inhibitor, as well as by xestospongin and 2-aminoethoxydiphenyl borate, two inositol trisphosphate (IP3) receptor inhibitors in the SR. These observations support the view that LPG-induced increase in [Ca2+]i in VSM cells is mainly a result of Ca2+ release from Ca2+ pool in the SR through PLC/IP3-sensitive signal transduction mechanism. Furthermore, it is suggested that the elevated level of LPG may induce intracellular Ca2+ overload and thus play a critical role in the development of vascular abnormalities.
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Affiliation(s)
- Ying Zhang
- a Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Xinmin Street No. 71, Changchun 130000, China
| | - Jing-Dian Zhang
- a Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Xinmin Street No. 71, Changchun 130000, China
| | - Ming-Qin Zhu
- a Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Xinmin Street No. 71, Changchun 130000, China
| | - Ming Zhang
- b Department of Pharmacology, College of Basic Medical Sciences, School of Nursing, Jilin University, Changchun 130021, China
| | - Yan-Jun Xu
- c Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre and Department of Physiology and Pathophysiology, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R2H 2A6, Canada
| | - Li Cui
- a Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Xinmin Street No. 71, Changchun 130000, China
| | - Naranjan S Dhalla
- c Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre and Department of Physiology and Pathophysiology, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R2H 2A6, Canada
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Xu YJ, Elimban V, Dhalla NS. Reduction of blood pressure by store-operated calcium channel blockers. J Cell Mol Med 2015; 19:2763-70. [PMID: 26471725 PMCID: PMC4687696 DOI: 10.1111/jcmm.12684] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 08/14/2015] [Indexed: 12/16/2022] Open
Abstract
The voltage-operated Ca(2+) channels (VOCC), which allow Ca(2+) influx from the extracellular space, are inhibited by anti-hypertensive agents such as verapamil and nifedipine. The Ca(2+) entering from outside into the cell triggers Ca(2+) release from the sarcoplasmic reticulum (SR) stores. To refill the depleted Ca(2+) stores in the SR, another type of Ca(2+) channels in the cell membrane, known as store-operated Ca(2+) channels (SOCC), are activated. These SOCCs are verapamil and nifedipine resistant, but are SKF 96465 (SK) and gadolinium (Gd(3+) ) sensitive. Both SK and Gd(3+) have been shown to reduce [Ca(2+) ]i in the smooth muscle, but their effects on blood pressure have not been reported. Our results demonstrated that both SK and Gd(3+) produced a dose-dependent reduction in blood pressure in rat. The combination of SK and verapamil produced an additive action in lowering the blood pressure. Furthermore, SK, but not Gd(3+) suppressed proliferation of vascular smooth muscle cells in the absence or presence of lysophosphatidic acid (LPA). SK decreased the elevation of [Ca(2+) ]i induced by LPA, endothelin-1 (ET-1) and angiotensin II (Ang II), but did not affect the norepinephrine (NE)-evoked increase in [Ca(2+) ]i . On the other hand, Gd(3+) inhibited the LPA and Ang II induced change in [Ca(2+) ]i , but had no effect on the ET-1 and NE induced increase in [Ca(2+) ]i . The combination of verapamil and SK abolished the LPA- or adenosine-5'-triphosphate (ATP)-induced [Ca(2+) ]i augmentation. These results suggest that SOCC inhibitors, like VOCC blocker, may serve as promising drugs for the treatment of hypertension.
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Affiliation(s)
- Yan-Jun Xu
- Institute of Cardiovascular Sciences, St. Boniface Hospital Research Centre, Department of Physiology and Pathophysiology, Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Vijayan Elimban
- Institute of Cardiovascular Sciences, St. Boniface Hospital Research Centre, Department of Physiology and Pathophysiology, Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Naranjan S Dhalla
- Institute of Cardiovascular Sciences, St. Boniface Hospital Research Centre, Department of Physiology and Pathophysiology, Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
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Zhao J, Wei J, Bowser RK, Dong S, Xiao S, Zhao Y. Molecular regulation of lysophosphatidic acid receptor 1 trafficking to the cell surface. Cell Signal 2014; 26:2406-11. [PMID: 25025571 DOI: 10.1016/j.cellsig.2014.07.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 07/09/2014] [Indexed: 01/20/2023]
Abstract
The lysophosphatidic acid receptor 1 (LPA1), a G-protein coupled receptor, regulates cell proliferation, migration, and cytokine release. Here, we investigate the molecular signature of LPA1 trafficking to the cell surface. The overexpressed LPA1 with a C-terminal V5 tag (LPA1-V5) is majorly expressed on the cell surface, while two deletion mutants (C320 and ∆84-87) failed to be trafficked to the cell surface. Further, site-directed mutagenesis analysis of the LPA1 revealed that Ile325, Tyr85, and Leu87 within these two fragments regulate LPA1 maturation and trafficking to the cell surface. Over-expression of Sar1, a component of coat protein complex II (COPII), enhances glycosylation of LPA1 wild type, but not these mutants. The mutants of LPA1 are majorly localized in the endoplasmic reticulum (ER) and exhibit a higher binding affinity to heat shock protein 70 (Hsp70), when compared to the LPA1 wild type. Further, we found that all these mutants failed to increase phosphorylation of Erk, and the cytokine release in response to LPA treatment. These results suggest that Ile325, Tyr85, and Leu87 within LPA1 are essential for LPA1 protein properly folding in the ER.
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Affiliation(s)
- Jing Zhao
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States
| | - Jianxin Wei
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States
| | - Rachel K Bowser
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States
| | - Su Dong
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States; Department of Anesthesia, First Hospital of Jilin University, Changchun, China
| | - Shuqi Xiao
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States
| | - Yutong Zhao
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States.
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Saini-Chohan HK, Hryshko L, Xu YJ, Dhalla NS. Modification of Ca(2+)-handling in cardiomyocytes by redox sensitive mechanisms in response to ouabain. Can J Physiol Pharmacol 2013; 91:45-55. [PMID: 23367872 DOI: 10.1139/cjpp-2012-0215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We examined the role of redox-sensitive signal transduction mechanisms in modifying the changes in [Ca(2+)](i) produced by ouabain upon incubating adult rat cardiomyocytes with antioxidants or inhibitors of different protein kinases and monitoring alterations in fura-2 fluorescence. Ouabain increased basal [Ca(2+)](i), augmented the KCl-induced increase in [Ca(2+)](i), and promoted oxyradical production in cardiomyocytes. These actions of ouabain were attenuated by an oxyradical scavenging mixture (superoxide dismutase plus catalase), and the antioxidants (N-acetyl-L-cysteine and N-(2-mercaptoproprionyl)glycine). An inhibitor of MAP kinase (PD98059) depressed the ouabain-induced increase in [Ca(2+)], whereas inhibitors of tyrosine kinase (tyrphostin and genistein) and PI3 kinase (Wortmannin and LV294002) enhanced the ouabain-induced increase in [Ca(2+)](i). Inhibitors of protein kinase C (calphostin and bisindolylmalaimide) augmented the ouabain-induced increase in [Ca(2+)](i), whereas stimulation of protein kinase C by a phorbol ester (phorbol 12-myristate 13-acetate) depressed the action of ouabain. These results suggest that ouabain-induced inhibition of Na (+)-K(+) ATPase may alter the redox status of cardiomyocytes through the production of oxyradicals, and increase the activities of various protein kinases. Thus, these redox-sensitive signal transduction mechanisms involving different protein kinases may modify Ca(2+)-handling sites in cardiomyocytes and determine the magnitude of net increase in [Ca(2+)](i) in response to ouabain.
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Affiliation(s)
- Harjot K Saini-Chohan
- Institute of Cardiovascular Sciences, St. Boniface Hospital Research and Department of Physiology, Faculty of Medicine, University of Manitoba, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
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Gaaya A, Poirier O, Mougenot N, Hery T, Atassi F, Marchand A, Saulnier-Blache JS, Amour J, Vogt J, Lompré AM, Soubrier F, Nadaud S. Plasticity-related gene-1 inhibits lysophosphatidic acid-induced vascular smooth muscle cell migration and proliferation and prevents neointima formation. Am J Physiol Cell Physiol 2012; 303:C1104-14. [DOI: 10.1152/ajpcell.00051.2012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Plasticity-related gene-1 (PRG-1) protects neuronal cells from lysophosphatidic acid (LPA) effects. In vascular smooth muscle cells (VSMCs), LPA was shown to induce phenotypic modulation in vitro and vascular remodeling in vivo. Thus we explored the role of PRG-1 in modulating VSMC response to LPA. PCR, Western blot, and immunofluorescence experiments showed that PRG-1 is expressed in rat and human vascular media. PRG-1 expression was strongly inhibited in proliferating compared with quiescent VSMCs both in vitro and in vivo (medial vs. neointimal VSMCs), suggesting that PRG-1 expression is dependent on the cell phenotype. In vitro, adenovirus-mediated overexpression of PRG-1 specifically inhibited LPA-induced rat VSMC proliferation and migration but not platelet-derived growth factor-induced proliferation. This effect was abolished by mutation of a conserved histidine in the lipid phosphate phosphatase family that is essential for interaction with lipid phosphates. In vivo, balloon-induced neointimal formation in rat carotid was significantly decreased in vessels infected with PRG-1 adenovirus compared with β-galactosidase adenovirus (−71%; P < 0.05). PRG-1 overexpression abolished the activation of the p42/p44 signaling pathway in LPA-stimulated rat VSMCs in culture and in balloon-injured rat carotids. Taken together, these findings provide the first evidence of a protective role of PRG-1 in the vascular media under pathophysiological conditions.
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Affiliation(s)
- Amira Gaaya
- INSERM, Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche UMR_S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
- UPMC Univ Paris 06, Université Pierre et Marie Curie, UMR-S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
| | - Odette Poirier
- INSERM, Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche UMR_S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
- UPMC Univ Paris 06, Université Pierre et Marie Curie, UMR-S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
| | - Nathalie Mougenot
- INSERM, Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche UMR_S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
- INSERM, Faculté de Médecine Pitié-Salpétrière, PECMV-IFR14, Paris, France
| | - Tiphaine Hery
- INSERM, Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche UMR_S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
- UPMC Univ Paris 06, Université Pierre et Marie Curie, UMR-S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
| | - Fabrice Atassi
- INSERM, Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche UMR_S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
- UPMC Univ Paris 06, Université Pierre et Marie Curie, UMR-S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
| | - Alexandre Marchand
- INSERM, Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche UMR_S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
- UPMC Univ Paris 06, Université Pierre et Marie Curie, UMR-S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
| | - Jean-Sébastien Saulnier-Blache
- INSERM, U1048/I2MC, Toulouse, France
- Université Toulouse III Paul Sabatier, Institut de Médecine Moléculaire de Rangueil, Toulouse, France
| | - Julien Amour
- INSERM, Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche UMR_S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
- Department of Anesthesiology and Critical Care Medicine, Centre Hospitalier Universitaire Pitié-Salpêtrière, Paris, France; and
| | - Johannes Vogt
- Institute for Microanatomy and Neurobiology, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Anne-Marie Lompré
- INSERM, Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche UMR_S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
- UPMC Univ Paris 06, Université Pierre et Marie Curie, UMR-S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
| | - Florent Soubrier
- INSERM, Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche UMR_S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
- UPMC Univ Paris 06, Université Pierre et Marie Curie, UMR-S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
| | - Sophie Nadaud
- INSERM, Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche UMR_S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
- UPMC Univ Paris 06, Université Pierre et Marie Curie, UMR-S 956, Faculté de Médecine Pitié-Salpétrière, Paris, France
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Panchatcharam M, Miriyala S, Salous A, Wheeler J, Dong A, Mueller P, Sunkara M, Escalante-Alcalde D, Morris AJ, Smyth SS. Lipid phosphate phosphatase 3 negatively regulates smooth muscle cell phenotypic modulation to limit intimal hyperplasia. Arterioscler Thromb Vasc Biol 2012; 33:52-9. [PMID: 23104851 DOI: 10.1161/atvbaha.112.300527] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECTIVE The lipid phosphate phosphatase 3 (LPP3) degrades bioactive lysophospholipids, including lysophosphatidic acid and sphingosine-1-phosphate, and thereby terminates their signaling effects. Although emerging evidence links lysophosphatidic acid to atherosclerosis and vascular injury responses, little is known about the role of vascular LPP3. The goal of this study was to determine the role of LPP3 in the development of vascular neointima formation and smooth muscle cells (SMC) responses. METHODS AND RESULTS We report that LPP3 is expressed in vascular SMC after experimental arterial injury. Using gain- and loss-of-function approaches, we establish that a major function of LPP3 in isolated SMC cells is to attenuate proliferation (extracellular signal-regulated kinases) activity, Rho activation, and migration in response to serum and lysophosphatidic acid. These effects are at least partially a consequence of LPP3-catalyzed lysophosphatidic acid hydrolysis. Mice with selective inactivation of LPP3 in SMC display an exaggerated neointimal response to injury. CONCLUSIONS Our observations suggest that LPP3 serves as an intrinsic negative regulator of SMC phenotypic modulation and inflammation after vascular injury, in part, by regulating lysophospholipid signaling. These findings may provide a mechanistic link to explain the association between a PPAP2B polymorphism and coronary artery disease risk.
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Affiliation(s)
- Manikandan Panchatcharam
- Division of Cardiovascular Medicine, The Gill Heart Institute, 255 BBRSB, 741 S. Limestone St, Lexington, KY 40536-0200, USA
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12
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Lysophosphatidic acid increases the electrophysiological instability of adult rabbit ventricular myocardium by augmenting L-type calcium current. PLoS One 2012; 7:e45862. [PMID: 23029283 PMCID: PMC3448719 DOI: 10.1371/journal.pone.0045862] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 08/22/2012] [Indexed: 01/17/2023] Open
Abstract
Lysophosphatidic acid (LPA) has diverse actions on the cardiovascular system and is widely reported to modulate multiple ion currents in some cell types. However, little is known about its electrophysiological effects on cardiac myocytes. This study investigated whether LPA has electrophysiological effects on isolated rabbit myocardial preparations. The results indicate that LPA prolongs action potential duration at 90% repolarization (APD90) in a concentration- and frequency-dependent manner in isolated rabbit ventricular myocytes. The application of extracellular LPA significantly increases the coefficient of APD90 variability. LPA increased L-type calcium current (ICa,L) density without altering its activation or deactivation properties. In contrast, LPA has no effect on two other ventricular repolarizing currents, the transient outward potassium current (Ito) and the delayed rectifier potassium current (IK). In arterially perfused rabbit left ventricular wedge preparations, the monophasic action potential duration, QT interval, and Tpeak-end are prolonged by LPA. LPA treatment also significantly increases the incidence of ventricular tachycardia induced by S1S2 stimulation. Notably, the effects of LPA on action potentials and ICa,L are PTX-sensitive, suggesting LPA action requires a Gi-type G protein. In conclusion, LPA prolongs APD and increases electrophysiological instability in isolated rabbit myocardial preparations by increasing ICa,L in a Gi protein-dependent manner.
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Wei Y, Liu SW, Zhao LQ, Zhou GQ, Chen SW, Li H. Lysophosphatidic acid as a potential trigger of atrial fibrillation. Med Hypotheses 2012; 79:649-52. [PMID: 22922058 DOI: 10.1016/j.mehy.2012.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 06/30/2012] [Accepted: 08/01/2012] [Indexed: 10/28/2022]
Abstract
Atrial fibrillation (AF) is the most common arrhythmia in clinical practice, but its pathogenesis is incompletely understood. Current evidences have highlighted the progression of atrial fibrosis and electrophysiological remodeling in AF development. Lysophosphatidic acid (LPA), the simplest phospholipid, is associated with fibrotic disease and promotes proliferation of a wide variety of fibroblast. It was demonstrated that LPA stimulation in many cell types such as human endothelial cells, human renal fibroblasts, and myoblasts, significantly upregulates connective tissue growth factor (CTGF) expression, which acts as a downstream signaling effector for transforming growth factor-β1 (TGF-β1) to drive fibrosis. We hypothesized that LPA could also evoke growth factor-like responses to atrial fibroblast, and subsequently induce atrial fibrosis to trigger AF. LPA is also verified to involve in numerous electrophysiological activities in non-myocardiocytes. So LPA is a possible cause of AF by initiating fibrosis response and altering electrophysiological properties in atrium. If the hypothesis is confirmed, LPA will act as a new target for AF treatment and administration of LPA receptor blockers may be applied in the prophylaxis of AF.
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Affiliation(s)
- Yong Wei
- Department of Cardiology, Shanghai First People's Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
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14
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Narayanan D, Adebiyi A, Jaggar JH. Inositol trisphosphate receptors in smooth muscle cells. Am J Physiol Heart Circ Physiol 2012; 302:H2190-210. [PMID: 22447942 DOI: 10.1152/ajpheart.01146.2011] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP(3)Rs) are a family of tetrameric intracellular calcium (Ca(2+)) release channels that are located on the sarcoplasmic reticulum (SR) membrane of virtually all mammalian cell types, including smooth muscle cells (SMC). Here, we have reviewed literature investigating IP(3)R expression, cellular localization, tissue distribution, activity regulation, communication with ion channels and organelles, generation of Ca(2+) signals, modulation of physiological functions, and alterations in pathologies in SMCs. Three IP(3)R isoforms have been identified, with relative expression and cellular localization of each contributing to signaling differences in diverse SMC types. Several endogenous ligands, kinases, proteins, and other modulators control SMC IP(3)R channel activity. SMC IP(3)Rs communicate with nearby ryanodine-sensitive Ca(2+) channels and mitochondria to influence SR Ca(2+) release and reactive oxygen species generation. IP(3)R-mediated Ca(2+) release can stimulate plasma membrane-localized channels, including transient receptor potential (TRP) channels and store-operated Ca(2+) channels. SMC IP(3)Rs also signal to other proteins via SR Ca(2+) release-independent mechanisms through physical coupling to TRP channels and local communication with large-conductance Ca(2+)-activated potassium channels. IP(3)R-mediated Ca(2+) release generates a wide variety of intracellular Ca(2+) signals, which vary with respect to frequency, amplitude, spatial, and temporal properties. IP(3)R signaling controls multiple SMC functions, including contraction, gene expression, migration, and proliferation. IP(3)R expression and cellular signaling are altered in several SMC diseases, notably asthma, atherosclerosis, diabetes, and hypertension. In summary, IP(3)R-mediated pathways control diverse SMC physiological functions, with pathological alterations in IP(3)R signaling contributing to disease.
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Affiliation(s)
- Damodaran Narayanan
- Department of Physiology, University of Tennessee Health Science Center, Memphis, 38163, USA
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15
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Chemoattraction to lysophosphatidic acid does not require a change in membrane potential inTetrahymena thermophila. Cell Biol Int 2011; 35:519-28. [DOI: 10.1042/cbi20100320] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Xu YJ, Tappia PS, Goyal RK, Dhalla NS. Mechanisms of the lysophosphatidic acid-induced increase in [Ca(2+)](i) in skeletal muscle cells. J Cell Mol Med 2008; 12:942-54. [PMID: 18494935 PMCID: PMC4401138 DOI: 10.1111/j.1582-4934.2008.00139.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Although lysophosphatidic acid (LPA) is known to increase intracellularfree calcium concentration ([Ca2+]i) in different cell types, the effect of LPA on the skeletal muscle cells is not known. The present study was therefore undertaken to examine the effect of LPA on the [Ca2+]i in C2C12 cells. LPA induced a concentration and time dependent increase in [Ca2+]i, which was inhibited by VPC12249, VPC 32183 and dioctanoyl glycerol pyrophosphate, LPA1/3 receptor antagonists. Pertussis toxin, a Gi protein inhibitor, also inhibited the LPA-induced increase in [Ca2+]i. Inhibition of tyrosine kinase activities with tyrphostin A9 and genistein also prevented the increase in [Ca2+]i due to LPA. Likewise, wortmannin and LY 294002, phosphatidylinositol 3-kinase (PI3-K) inhibitors, inhibited [Ca2+]i response to LPA. The LPA effect was also attenuated by ethylene glycolbis(β-aminoethylether)-N,N,N′,N′-tetraacetic acid (EGTA), an extracellular Ca2+ chelator, Ni2+ and KB-R7943, inhibitors of the Na+-Ca2+ exchanger; the receptor operated Ca2+ channel (ROC) blockers, 2-aminoethoxydiphenyl borate and SK&F 96365. However, the L-type Ca2+ channel blockers, verapamil and diltiazem; the store operated Ca2+ channel blockers, La3+ and Gd3+; a sarcoplasmic reticulum calcium pump inhibitor, thapsigargin; an inositol trisphosphate receptor antagonist, xestospongin and a phospholipase C inhibitor, U73122, did not prevent the increase [Ca2+]i due to LPA. Our data suggest that the LPA-induced increase in [Ca2+]i might occur through Gi-protein coupled LPA1/3 receptors that may be linked to tyrosine kinase and PI3-K, and may also involve the Na+-Ca2+ exchanger as well as the ROC. In addition, LPA stimulated C2C12 cell proliferation via PI3-K. Thus, LPA may be an important phospholipid in the regulation of [Ca2+]i and growth of skeletal muscle cells.
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Affiliation(s)
- Yan-Jun Xu
- Institute of Cardiovascular Sciences, St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada
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Lysophosphatidic acid-induced transactivation of epidermal growth factor receptor regulates cyclo-oxygenase-2 expression and prostaglandin E(2) release via C/EBPbeta in human bronchial epithelial cells. Biochem J 2008; 412:153-62. [PMID: 18294142 DOI: 10.1042/bj20071649] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We have demonstrated that LPA (lysophosphatidic acid)-induced IL (interleukin)-8 secretion was partly mediated via transactivation of EGFR [EGF (epidermal growth factor) receptor] in HBEpCs (human bronchial epithelial primary cells). The present study provides evidence that LPA-induced transactivation of EGFR regulates COX (cyclo-oxygenase)-2 expression and PGE(2) [PG (prostaglandin) E(2)] release through the transcriptional factor, C/EBPbeta (CCAAT/enhancer-binding protein beta), in HBEpCs. Treatment with LPA (1 microM) stimulated COX-2 mRNA and protein expression and PGE(2) release via G(alphai)-coupled LPARs (LPA receptors). Pretreatment with inhibitors of NF-kappaB (nuclear factor-kappaB), JNK (Jun N-terminal kinase), or down-regulation of c-Jun or C/EBPbeta with specific siRNA (small interference RNA) attenuated LPA-induced COX-2 expression. Downregulation of EGFR by siRNA or pretreatment with the EGFR tyrosine kinase inhibitor, AG1478, partly attenuated LPA-induced COX-2 expression and phosphorylation of C/EBPbeta; however, neither of these factors had an effect on the NF-kappaB and JNK pathways. Furthermore, LPA-induced EGFR transactivation, phosphorylation of C/EBPbeta and COX-2 expression were attenuated by overexpression of a catalytically inactive mutant of PLD2 [PLD (phospholipase D) 2], PLD2-K758R, or by addition of myristoylated PKCzeta [PKC (protein kinase C) zeta] peptide pseudosubstrate. Overexpression of the PLD2-K758R mutant also attenuated LPA-induced phosphorylation and activation of PKCzeta. These results demonstrate that LPA induces COX-2 expression and PGE(2) production through EGFR transactivation-independent activation of transcriptional factors NF-kappaB and c-Jun, and EGFR transactivation-dependent activation of C/EBPbeta in HBEpCs. Since COX-2 and PGE(2) have been shown to be anti-inflammatory in airway inflammation, the present data suggest a modulating and protective role of LPA in regulating innate immunity and remodelling of the airways.
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Saini HK, Dhalla NS. Sarcolemmal cation channels and exchangers modify the increase in intracellular calcium in cardiomyocytes on inhibiting Na+-K+-ATPase. Am J Physiol Heart Circ Physiol 2007; 293:H169-81. [PMID: 17322410 DOI: 10.1152/ajpheart.00007.2007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Although inhibition of the sarcolemmal (SL) Na+-K+-ATPase is known to cause an increase in the intracellular concentration of Ca2+([Ca2+]i) by stimulating the SL Na+/Ca2+exchanger (NCX), the involvement of other SL sites in inducing this increase in [Ca2+]iis not fully understood. Isolated rat cardiomyocytes were treated with or without different agents that modify Ca2+movements by affecting various SL sites and were then exposed to ouabain. Ouabain was observed to increase the basal levels of both [Ca2+]iand intracellular Na+concentration ([Na+]i) as well as to augment the KCl-induced increases in both [Ca2+]iand [Na+]iin a concentration-dependent manner. The ouabain-induced changes in [Na+]iand [Ca2+]iwere attenuated by treatment with inhibitors of SL Na+/H+exchanger and SL Na+channels. Both the ouabain-induced increase in basal [Ca2+]iand augmentation of the KCl response were markedly decreased when cardiomyocytes were exposed to 0–10 mM Na+. Inhibitors of SL NCX depressed but decreasing extracellular Na+from 105–35 mM augmented the ouabain-induced increase in basal [Ca2+]iand the KCl response. Not only was the increase in [Ca2+]iby ouabain dependent on the extracellular Ca2+concentration, but it was also attenuated by inhibitors of SL L-type Ca2+channels and store-operated Ca2+channels (SOC). Unlike the SL L-type Ca2+-channel blocker, the blockers of SL Na+channel and SL SOC, when used in combination with SL NCX inhibitor, showed additive effects in reducing the ouabain-induced increase in basal [Ca2+]i. These results support the view that in addition to SL NCX, SL L-type Ca2+channels and SL SOC may be involved in raising [Ca2+]ion inhibition of the SL Na+-K+-ATPase by ouabain. Furthermore, both SL Na+/H+exchanger and Na+channels play a critical role in the ouabain-induced Ca2+increase in cardiomyocytes.
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Affiliation(s)
- Harjot K Saini
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, 351 Tache Avenue, Winnipeg, Manitoba, Canada
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Xu L, Yu BP, Chen JG, Luo HS. Mechanisms mediating serotonin-induced contraction of colonic myocytes. Clin Exp Pharmacol Physiol 2007; 34:120-8. [PMID: 17201746 DOI: 10.1111/j.1440-1681.2007.04465.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: 01/11/2023]
Abstract
1. 5-Hydroxytryptamine (5-HT) has an important role in the pathogenesis of irritable bowel syndrome. To investigate the effects of 5-HT on the contractile activity of myocytes of the guinea-pig proximal colon, cell imaging before and after contraction was undertaken and images were analysed using image-analysis software. Ion currents and membrane potentials were measured. Cytoplasmic free Ca(2+) was recorded using a confocal microscope following loading of the cells with the fluorescent probe Fura-2AM. 2. 5-Hydroxytryptamine reduced cell length in a dose-dependent manner (EC(50) = 0.189 micromol/L). Under current clamp, 10 micromol/L 5-HT reduced action potential amplitude (measured as peak height) and decreased action potential duration, as well as depolarizing the resting potential from -68.4 +/- 3.6 to -22.96 +/- 4.65 mV. Iberiotoxin (1 micromol/L) blocked the effects of 5-HT in reducing the time to repolarization (T(90)) and nicardipine (5 micromol/L) blocked the effects of 5-HT in reducing action potential amplitude. 3. In the whole-cell mode, 5-HT enhanced L-type Ca(2+) currents, large conductance K(+) channel (BK(Ca)) currents and spontaneous transient outward currents (STOC). In addition, 5-HT increased intracellular Ca(2+) levels. Ondansetron (10 micromol/L) blocked the effects of 5-HT in enhancing L-type Ca(2+) currents, BK(Ca) currents and STOC. 4. In conclusion, 5-HT induces contraction of colonic myocytes, mostly as a result of Ca(2+) release from the sarcoplasmic reticulum (SR) following activation of 5-HT(3) receptors and the inositol 1,4,5-trisphosphate pathway. In addition, the effect of 5-HT in decreasing action potential amplitude is mediated by the release of Ca(2+) from the SR, as well as by enhanced L-type Ca(2+) current. 5-Hydroxytryptamine decreased action potential duration by enhancing BK(Ca) current.
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Affiliation(s)
- Long Xu
- Department of Gastroenterology, Renmin Hospital, Wuhan University, Wuhan, China
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20
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Zhao Y, He D, Zhao J, Wang L, Leff AR, Spannhake EW, Georas S, Natarajan V. Lysophosphatidic acid induces interleukin-13 (IL-13) receptor alpha2 expression and inhibits IL-13 signaling in primary human bronchial epithelial cells. J Biol Chem 2007; 282:10172-9. [PMID: 17287216 PMCID: PMC2659592 DOI: 10.1074/jbc.m611210200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Interleukin-13 (IL-13), a Th2 cytokine, plays a pivotal role in pathogenesis of bronchial asthma via IL-13 receptor alpha1 (IL-13Ralpha1) and IL-4 receptor alpha (IL-4Ralpha). Recent studies show that a decoy receptor for IL-13, namely IL-13Ralpha2, mitigates IL-13 signaling and function. This study provides evidence for regulation of IL-13Ralpha2 production and release and IL-13-dependent signaling by lysophosphatidic acid (LPA) in primary cultures of human bronchial epithelial cells (HBEpCs). LPA treatment of HBEpCs in at imedependent fashion increased IL-13Ralpha2 gene expression without altering the mRNA levels of IL-13Ralpha1 and IL-4Ralpha. Pretreatment with pertussis toxin (100 ng/ml, 4 h) or transfection of c-Jun small interference RNA or an inhibitor of JNK attenuated LPA-induced IL-13Ralpha2 gene expression and secretion of soluble IL-13Ralpha2. Overexpression of catalytically inactive mutants of phospholipase D (PLD) 1 or 2 attenuated LPA-induced IL-13Ralpha2 gene expression and protein secretion as well as phosphorylation of JNK. Pretreatment of HBEpCs with 1 microM LPA for 6 h attenuated IL-13-but not IL-4-induced phosphorylation of STAT6. Transfection of HBEpCs with IL-13Ralpha2 small interference RNA blocked the effect of LPA on IL-13-induced phosphorylation of STAT6. Furthermore, pretreatment with LPA (1 microM, 6 h) attenuated IL-13-induced eotaxin-1 and SOCS-1 gene expression. These results demonstrate that LPA induces IL-13Ralpha2 expression and release via PLD and JNK/AP-1 signal transduction and that pretreatment with LPA down-regulates IL-13 signaling in HBEpCs. Our data suggest a novel mechanism of regulation of IL-13Ralpha2 and IL-13 signaling that may be of physiological relevance to airway inflammation and remodeling.
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Affiliation(s)
- Yutong Zhao
- Section of Pulmonary and Critical Care, Department of Medicine, University of Chicago, Chicago, Illinois 60637, USA.
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Tappia PS, Singal T, Dent MR, Asemu G, Mangat R, Dhalla NS. Phospholipid-mediated signaling in diseased myocardium. ACTA ACUST UNITED AC 2006. [DOI: 10.2217/17460875.1.6.701] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Saini HK, Dhalla NS. Modification of intracellular calcium concentration in cardiomyocytes by inhibition of sarcolemmal Na+/H+exchanger. Am J Physiol Heart Circ Physiol 2006; 291:H2790-800. [PMID: 16861694 DOI: 10.1152/ajpheart.00535.2006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although the Na+/H+exchanger (NHE) is considered to be involved in regulation of intracellular Ca2+concentration ([Ca2+]i) through the Na+/Ca2+exchanger, the exact mechanisms of its participation in Ca2+handling by cardiomyocytes are not fully understood. Isolated rat cardiomyocytes were treated with or without agents that are known to modify Ca2+movements in cardiomyocytes and exposed to an NHE inhibitor, 5-( N-methyl- N-isobutyl)amiloride (MIA). [Ca2+]iin cardiomyocytes was measured spectrofluorometrically with fura 2-AM in the absence or presence of KCl, a depolarizing agent. MIA increased basal [Ca2+]iand augmented the KCl-induced increase in [Ca2+]iin a concentration-dependent manner. The MIA-induced increase in basal [Ca2+]iwas unaffected by extracellular Ca2+, antagonists of the sarcolemmal (SL) L-type Ca2+channel, and inhibitors of the SL Na+/Ca2+exchanger, SL Ca2+pump ATPase and mitochondrial Ca2+uptake. However, the MIA-induced increase in basal [Ca2+]iwas attenuated by inhibitors of SL Na+-K+-ATPase and sarcoplasmic reticulum (SR) Ca2+transport. On the other hand, the MIA-mediated augmentation of the KCl response was dependent on extracellular Ca2+concentration and attenuated by agents that inhibit SL L-type Ca2+channels, the SL Na+/Ca2+exchanger, SL Na+-K+-ATPase, and SR Ca2+release channels and the SR Ca2+pump. However, the effect of MIA on the KCl-induced increase in [Ca2+]iremained unaffected by treatment with inhibitors of SL Ca2+pump ATPase and mitochondrial Ca2+uptake. MIA and a decrease in extracellular pH lowered intracellular pH and increased basal [Ca2+]i, whereas a decrease in extracellular pH, in contrast to MIA, depressed the KCl-induced increase in [Ca2+]iin cardiomyocytes. These results suggest that NHE may be involved in regulation of [Ca2+]iand that MIA-induced increases in basal [Ca2+]i, as well as augmentation of the KCl-induced increase in [Ca2+]i, in cardiomyocytes are regulated differentially.
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Affiliation(s)
- Harjot K Saini
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, University of Manitoba, Winnipeg, MB, Canada R2H 2A6
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