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Wong GS, Redes JL, Balenga N, McCullough M, Fuentes N, Gokhale A, Koziol-White C, Jude JA, Madigan LA, Chan EC, Jester WH, Biardel S, Flamand N, Panettieri RA, Druey KM. RGS4 promotes allergen- and aspirin-associated airway hyperresponsiveness by inhibiting PGE2 biosynthesis. J Allergy Clin Immunol 2020; 146:1152-1164.e13. [PMID: 32199913 DOI: 10.1016/j.jaci.2020.03.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 02/21/2020] [Accepted: 03/11/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Allergens elicit host production of mediators acting on G-protein-coupled receptors to regulate airway tone. Among these is prostaglandin E2 (PGE2), which, in addition to its role as a bronchodilator, has anti-inflammatory actions. Some patients with asthma develop bronchospasm after the ingestion of aspirin and other nonsteroidal anti-inflammatory drugs, a disorder termed aspirin-exacerbated respiratory disease. This condition may result in part from abnormal dependence on the bronchoprotective actions of PGE2. OBJECTIVE We sought to understand the functions of regulator of G protein signaling 4 (RGS4), a cytoplasmic protein expressed in airway smooth muscle and bronchial epithelium that regulates the activity of G-protein-coupled receptors, in asthma. METHODS We examined RGS4 expression in human lung biopsies by immunohistochemistry. We assessed airways hyperresponsiveness (AHR) and lung inflammation in germline and airway smooth muscle-specific Rgs4-/- mice and in mice treated with an RGS4 antagonist after challenge with Aspergillus fumigatus. We examined the role of RGS4 in nonsteroidal anti-inflammatory drug-associated bronchoconstriction by challenging aspirin-exacerbated respiratory disease-like (ptges1-/-) mice with aspirin. RESULTS RGS4 expression in respiratory epithelium is increased in subjects with severe asthma. Allergen-induced AHR was unexpectedly diminished in Rgs4-/- mice, a finding associated with increased airway PGE2 levels. RGS4 modulated allergen-induced PGE2 secretion in human bronchial epithelial cells and prostanoid-dependent bronchodilation. The RGS4 antagonist CCG203769 attenuated AHR induced by allergen or aspirin challenge of wild-type or ptges1-/- mice, respectively, in association with increased airway PGE2 levels. CONCLUSIONS RGS4 may contribute to the development of AHR by reducing airway PGE2 biosynthesis in allergen- and aspirin-induced asthma.
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Affiliation(s)
- Gordon S Wong
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases (NIAID)/National Institutes of Health (NIH), Bethesda, Md
| | - Jamie L Redes
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases (NIAID)/National Institutes of Health (NIH), Bethesda, Md
| | - Nariman Balenga
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases (NIAID)/National Institutes of Health (NIH), Bethesda, Md
| | - Morgan McCullough
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases (NIAID)/National Institutes of Health (NIH), Bethesda, Md
| | - Nathalie Fuentes
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases (NIAID)/National Institutes of Health (NIH), Bethesda, Md
| | - Ameya Gokhale
- Food Allergy Research Unit, Laboratory of Allergic Diseases, NIAID/NIH, Bethesda, Md
| | - Cynthia Koziol-White
- Rutgers Institute for Translational Medicine and Science, Child Health Institute of New Jersey, Rutgers University School of Medicine, New Brunswick, NJ
| | - Joseph A Jude
- Rutgers Institute for Translational Medicine and Science, Child Health Institute of New Jersey, Rutgers University School of Medicine, New Brunswick, NJ
| | - Laura A Madigan
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases (NIAID)/National Institutes of Health (NIH), Bethesda, Md
| | - Eunice C Chan
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases (NIAID)/National Institutes of Health (NIH), Bethesda, Md
| | - William H Jester
- Rutgers Institute for Translational Medicine and Science, Child Health Institute of New Jersey, Rutgers University School of Medicine, New Brunswick, NJ
| | - Sabrina Biardel
- Centre de recherche de l'IUCPQ, Département de médecine, Faculté de médecine, Université Laval, Québec, Canada
| | - Nicolas Flamand
- Centre de recherche de l'IUCPQ, Département de médecine, Faculté de médecine, Université Laval, Québec, Canada
| | - Reynold A Panettieri
- Rutgers Institute for Translational Medicine and Science, Child Health Institute of New Jersey, Rutgers University School of Medicine, New Brunswick, NJ
| | - Kirk M Druey
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases (NIAID)/National Institutes of Health (NIH), Bethesda, Md.
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Hagras MM, Kamel FO. Effect of Protease-Activated Receptor-2-Activating Peptide on Guinea Pig Airway Resistance and Isolated Tracheal Strips. J Microsc Ultrastruct 2019; 8:7-13. [PMID: 32166058 PMCID: PMC7045621 DOI: 10.4103/jmau.jmau_55_18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Accepted: 12/10/2018] [Indexed: 12/31/2022] Open
Abstract
Purpose: Protease-activated receptors (PARs) are a family of G-protein-coupled receptors distributed in a number of tissues. PAR-2 is expressed on airway epithelium and smooth muscles and overexpressed under pathological conditions, such as asthma and chronic obstructive pulmonary disease. However, the role of PAR-2 in airways has not yet been defined. In this study, we investigated the role of PAR-2-activating peptide (SLIGRL) on histamine-induced bronchoconstriction and the mechanisms underlying the bronchoprotective effect both in vivo and in vitro. Materials and Methods: The effect of SLIGRL was tested in vivo using histamine-induced bronchoconstriction in the guinea pig and in vitro using isolated tracheal spiral strips. Results: In vivo pretreatment with SLIGRL significantly reduced the histamine-induced increased bronchoconstriction. Neither propranolol nor vagotomy abolished the inhibitory effect of SLIGRL. Furthermore, indomethacin or glibenclamide did not antagonize the inhibitory response to SLIGRL. In isolated tracheal spiral strips in vitro, SLIGRL did not affect the contractile response to acetylcholine or potassium chloride; however, histamine-induced contraction was inhibited in a dose-dependent manner. Conclusion: Our data demonstrate the protective effect of SLIGRL in airways; however, this effect appears to be mediated independently of prostanoids, nitric oxide, circulating adrenaline, ATP-sensitive K + channels, and vagal stimulation.
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Affiliation(s)
- Magda M Hagras
- Department of Pharmacology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Fatemah O Kamel
- Department of Pharmacology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
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Jang JY, Kim YS, Han YM, Kang SY, Kim JS. Alteration in Uterine Protease-Activated Receptor 2 Expression in Preterm Birth Induced Experimentally in Brp-39 Null Mutant Mice. Reprod Sci 2018; 26:713-723. [PMID: 29996695 DOI: 10.1177/1933719118787036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Breast regression protein 39 (Brp-39) is a mouse homolog of human Chitinase 3-like 1, which belongs to the 18-glycosyl-hydrolase family and plays a role in inflammatory reaction and tissue remodeling. The aim of this study is to investigate the role of Brp-39 in a mouse model of preterm birth. Pregnant wild-type (WT) or Brp-39(-/-) mice were injected intraperitoneally with lipopolysaccharide (LPS) at embryonic day 15. Pregnancy outcomes were evaluated for 24 hours after LPS injection. Quantitative real-time polymerase chain reaction and immunoblotting were performed to analyze messenger RNA (mRNA) and protein expressions of cytokines and contraction-associated proteins in uterine and/or placental tissue after LPS injection. LPS injection led to preterm birth in both WT and Brp-39(-/-) mice, but the proportion of pubs delivered was reduced in Brp-39(-/-) mice, along with a longer interval from the LPS injection to delivery, compared to WT mice. Inflammatory cell infiltration and mRNA expression of cytokines and Ptgs2 in the uteri and the placentas were not significantly different between WT and Brp-39(-/-) mice. Par-2 mRNA expression in the WT uteri was increased before delivery after LPS injection and decreased after delivery, while there was no significant change in Par-2 expression in the Brp-39(-/-) uteri. Protein expressions of Par-2 and Ptgs2 were lower in the Brp-39(-/-) uteri than in the WT uteri before and after delivery. Attenuated preterm birth in Brp-39(-/-) mice indicates the significance of Brp-39 during murine preterm birth. Altered expression of Par-2 in Brp-39(-/-) uteri suggests its potential role in attenuated preterm birth of Brp-39(-/-) mice.
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Affiliation(s)
- Ja Yun Jang
- Department of Health Sciences and Technology, Sungkyunkwan University, SAIHST, Seoul, Republic of Korea
| | - Yi Seul Kim
- Department of Health Sciences and Technology, Sungkyunkwan University, SAIHST, Seoul, Republic of Korea
| | - Yu Mi Han
- Sungkyunkwan University School of Medicine, Research Institute of Medical Science, Seoul, Republic of Korea
| | - So Young Kang
- Department of Pathology and Translational Genomics, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul, 06351, Republic of Korea
| | - Jung-Sun Kim
- Department of Health Sciences and Technology, Sungkyunkwan University, SAIHST, Seoul, Republic of Korea. .,Department of Pathology and Translational Genomics, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul, 06351, Republic of Korea.
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Walker JKL, DeFea KA. Role for β-arrestin in mediating paradoxical β2AR and PAR2 signaling in asthma. Curr Opin Pharmacol 2014; 16:142-7. [PMID: 24907413 DOI: 10.1016/j.coph.2014.03.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 03/26/2014] [Accepted: 03/27/2014] [Indexed: 01/14/2023]
Abstract
G protein-coupled receptors (GPCRs) utilize (at least) two signal transduction pathways to elicit cellular responses including the classic G protein-dependent, and the more recently discovered β-arrestin-dependent, signaling pathways. In human and murine models of asthma, agonist-activation of β2-adrenergic receptor (β2AR) or Protease-activated-receptor-2 (PAR2) results in relief from bronchospasm via airway smooth muscle relaxation. However, chronic activation of these receptors, leads to pro-inflammatory responses. One plausible explanation underlying the paradoxical effects of β2AR and PAR2 agonism in asthma is that the beneficial and harmful effects are associated with distinct signaling pathways. Specifically, G protein-dependent signaling mediates relaxation of airway smooth muscle, whereas β-arrestin-dependent signaling promotes inflammation. This review explores the evidence supporting the hypothesis that β-arrestin-dependent signaling downstream of β2AR and PAR2 is detrimental in asthma and examines the therapeutic opportunities for selectively targeting this pathway.
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Affiliation(s)
- Julia K L Walker
- Duke University School of Nursing, Duke University Medical Center, Durham, NC 27710, USA.
| | - Katherine A DeFea
- Division of Biomedical Sciences, University of California, Riverside, CA 92521, USA
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Role of protease-activated receptor-2 on cell death and DNA fragmentation in Helicobacter pylori-infected gastric epithelial cells. J Transl Med 2010; 8:85. [PMID: 20846373 PMCID: PMC2945981 DOI: 10.1186/1479-5876-8-85] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Accepted: 09/16/2010] [Indexed: 12/16/2022] Open
Abstract
Background Helicobacter pylori (H. pylori) infection is associated with chronic gastritis, peptic ulceration and gastric carcinoma. Protease-activated receptor-2 (PAR-2), which is activated by trypsin, induced the activation of mitogen-activated protein kinases (MAPK), cell proliferation and apoptosis in several cells. Previously, we found that H. pylori induces the expression of PAR-2, which mediates the expression of adhesion molecules integrins in gastric epithelial cells. In the present study, the role of PAR-2 on H. pylori-induced cell death was investigated by determining cell viability, DNA fragmentation, and the activation of MAPK in gastric epithelial AGS cells. Methods AGS cells were cultured in the presence of H. pylori transfected with PAR-2 antisense (AS) oligonucleotide (ODN) or treated with a soybean trypsin inhibitor (SBTI). Viable cells and DNA fragmentation were determined by trypan blue exclusion assay and the amount of oligonucleosome-bound DNA, respectively. The activation of MAPK such as extracellular signal-regulated kinases (ERK), p38, and c-Jun N-terminal kinases (JNK), was assessed by Western blotting for phospho-specific forms of MAPK. Results H. pylori-induced cell death and DNA fragmentation augmented in the cells transfected with PAR-2 AS ODN or treated with SBTI. The activation of MAPK, induced by H. pylori, were suppressed by transfection with PAR-2 AS ODN or treatment with SBTI. Conclusion PAR-2, whose expression is induced by H. pylori, may prevent cell death and DNA fragmentation with the activation of MAPK in gastric epithelial cells.
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Peters T, Henry PJ. Protease-activated receptors and prostaglandins in inflammatory lung disease. Br J Pharmacol 2009; 158:1017-33. [PMID: 19845685 PMCID: PMC2785524 DOI: 10.1111/j.1476-5381.2009.00449.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 06/11/2009] [Accepted: 07/08/2009] [Indexed: 12/17/2022] Open
Abstract
Protease-activated receptors (PARs) are a novel family of G protein-coupled receptors. Signalling through PARs typically involves the cleavage of an extracellular region of the receptor by endogenous or exogenous proteases, which reveals a tethered ligand sequence capable of auto-activating the receptor. A considerable body of evidence has emerged over the past 20 years supporting a prominent role for PARs in a variety of human physiological and pathophysiological processes, and thus substantial attention has been directed towards developing drug-like molecules that activate or block PARs via non-proteolytic pathways. PARs are widely expressed within the respiratory tract, and their activation appears to exert significant modulatory influences on the level of bronchomotor tone, as well as on the inflammatory processes associated with a range of respiratory tract disorders. Nevertheless, there is debate as to whether the principal response to PAR activation is an augmentation or attenuation of airways inflammation. In this context, an important action of PAR activators may be to promote the generation and release of prostanoids, such as prostglandin E(2), which have well-established anti-inflammatory effects in the lung. In this review, we primarily focus on the relationship between PARs, prostaglandins and inflammatory processes in the lung, and highlight their potential role in selected respiratory tract disorders, including pulmonary fibrosis, asthma and chronic obstructive pulmonary disease.
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Affiliation(s)
- Terence Peters
- School of Medicine and Pharmacology, University of Western Australia, Nedlands, Australia
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Wang ZY, Wang P, Bjorling DE. Role of mast cells and protease-activated receptor-2 in cyclooxygenase-2 expression in urothelial cells. Am J Physiol Regul Integr Comp Physiol 2009; 297:R1127-35. [PMID: 19675284 DOI: 10.1152/ajpregu.00310.2009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Mast cells have been shown to play a role in development and persistence of various inflammatory bladder disorders. Mast cell-derived tryptase specifically activates protease-activated receptor-2 (PAR-2), and PAR-2 is known to be involved in inflammation. We investigated whether mast cells participate in increase of cyclooxygenase-2 (COX-2) protein abundance in urothelium/suburothelium of bladders of mice subsequent to cyclophosphamide (CYP)-induced bladder inflammation. We also used primary cultures of human urothelial cells to investigate cellular mechanisms underlying activation of PAR-2 resulting in increased COX-2 expression. We found that treatment of mice with CYP (150 mg/kg ip) increased COX-2 protein abundance in bladder urothelium/suburothelium 3, 6, and 24 h after CYP (P < 0.01), and increased COX-2 protein abundance was prevented by treatment of mice with the mast cell stabilizer sodium cromolyn (10 mg/kg ip) for 4 consecutive days before CYP treatment. Incubation of freshly isolated mouse urothelium/suburothelium with a selective PAR-2 agonist, 2-furoyl-LIGRLO-amide (3 microM), also increased COX-2 protein abundance (P < 0.05). We further demonstrated that 2-furoyl-LIGRLO-amide (3 microM) increased COX-2 mRNA expression and protein abundance in primary cultures of human urothelial cells (P < 0.01), and the effects of PAR-2 activation were mediated primarily by the ERK1/2 MAP kinase pathway. These data indicate that there are functional interactions among mast cells, PAR-2 activation, and increased expression of COX-2 in bladder inflammation.
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Affiliation(s)
- Zun-Yi Wang
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53719, USA.
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van der Merwe JQ, Moreau F, MacNaughton WK. Protease-activated receptor-2 stimulates intestinal epithelial chloride transport through activation of PLC and selective PKC isoforms. Am J Physiol Gastrointest Liver Physiol 2009; 296:G1258-66. [PMID: 19359428 DOI: 10.1152/ajpgi.90425.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Serine proteases play important physiological roles through their activity at G protein-coupled protease-activated receptors (PARs). We examined the roles that specific phospholipase (PL) C and protein kinase (PK) C (PKC) isoforms play in the regulation of PAR(2)-stimulated chloride secretion in intestinal epithelial cells. Confluent SCBN epithelial monolayers were grown on Snapwell supports and mounted in modified Ussing chambers. Short-circuit current (I(sc)) responses to basolateral application of the selective PAR(2) activating peptide, SLIGRL-NH(2), were monitored as a measure of net electrogenic ion transport caused by PAR(2) activation. SLIGRL-NH(2) induced a transient I(sc) response that was significantly reduced by inhibitors of PLC (U73122), phosphoinositol-PLC (ET-18), phosphatidylcholine-PLC (D609), and phosphatidylinositol 3-kinase (PI3K; LY294002). Immunoblot analysis revealed the phosphorylation of both PLCbeta and PLCgamma following PAR(2) activation. Pretreatment of the cells with inhibitors of PKC (GF 109203X), PKCalpha/betaI (Gö6976), and PKCdelta (rottlerin), but not PKCzeta (selective pseudosubstrate inhibitor), also attenuated this response. Cellular fractionation and immunoblot analysis, as well as confocal immunocytochemistry, revealed increases of PKCbetaI, PKCdelta, and PKCepsilon, but not PKCalpha or PKCzeta, in membrane fractions following PAR(2) activation. Pretreatment of the cells with U73122, ET-18, or D609 inhibited PKC activation. Inhibition of PI3K activity only prevented PKCdelta translocation. Immunoblots revealed that PAR(2) activation induced phosphorylation of both cRaf and ERK1/2 via PKCdelta. Inhibition of PKCbetaI and PI3K had only a partial effect on this response. We conclude that basolateral PAR(2)-induced chloride secretion involves activation of PKCbetaI and PKCdelta via a PLC-dependent mechanism resulting in the stimulation of cRaf and ERK1/2 signaling.
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van der Merwe JQ, Ohland CL, Hirota CL, MacNaughton WK. Prostaglandin E2 derived from cyclooxygenases 1 and 2 mediates intestinal epithelial ion transport stimulated by the activation of protease-activated receptor 2. J Pharmacol Exp Ther 2009; 329:747-52. [PMID: 19190238 DOI: 10.1124/jpet.108.145466] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Proteinase-activated receptor (PAR)(2) is activated by trypsin-like serine proteinases and has been implicated in intestinal inflammation. However, its role in the regulation of intestinal mucosal function remains unclear. Using the intestinal epithelial cell line, SCBN, we have studied the stimulus-secretion coupling mechanisms of PAR(2)-induced epithelial chloride transport, focusing on cyclooxygenase (COX)-1 and COX-2 activities and prostaglandin (PG) E(2) secretion. SCBN monolayers were grown on Snapwell supports, mounted in modified Ussing chambers, and exposed to the activating peptide, SLIGRL-NH(2) (50 microM), to activate PAR(2). Pretreatment with inhibitors of cytosolic PLA(2) (cPLA(2)) (AACOCF3, arachidonyltrifluoromethyl ketone), COX-1 [SC560, 5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-(trifluoromethyl)-1H-pyrazole], and COX-2 (celecoxib) resulted in a significant concentration-dependent attenuation of PAR(2)-induced changes in short-circuit current. Immunoblot analysis showed a PAR(2)-induced increase in cPLA(2) phosphorylation that was blocked by the mitogen-activated protein kinase kinase inhibitor, PD98059 [2-(2-amino-3methoxyphenyl)-4H-1benzopyran-4-one, C(16)H(13)NO(3)], and the pan-protein kinase C inhibitor, GFX (bisindolylmaleimide). PAR(2) stimulation also resulted in a large increase in the production of PGE(2) as determined by enzyme-linked immunosorbent assay and was also blocked by PD98059 and GFX. Immunofluorescence and immunoblot analysis determined that EP2 and EP4 are expressed at the basolateral membrane of SCBN cells. Through the use of selective inhibitors (EP2, AH6809 [6-isopropoxy-9-oxoxanthene-2-carboxylic acid]; EP4, GW627368X [N-[2[4,9-diethoxy-1-oxo-1,3-dihydro-2H-benzo[f]isoindol-2-yl)phenyl] acetyl]benzene sulphonamide]), it was found that both EP2 and EP4 were involved in mediating the PAR(2)-induced chloride secretory response. We conclude that basolateral PAR(2) activation induces epithelial chloride secretion that is mediated by cPLA(2), COX-1, COX-2, and the subsequent release of PGE(2). The production of PGE(2) results in an autocrine secretory response that is dependent on basolateral EP2 and EP4 receptors.
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Nagataki M, Moriyuki K, Sekiguchi F, Kawabata A. Evidence that PAR2-triggered prostaglandin E2 (PGE2) formation involves the ERK-cytosolic phospholipase A2-COX-1-microsomal PGE synthase-1 cascade in human lung epithelial cells. Cell Biochem Funct 2008; 26:279-82. [PMID: 17708577 DOI: 10.1002/cbf.1434] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We investigated possible involvement of three isozymes of prostaglandin E synthase (PGES), microsomal PGES-1 (mPGES-1), mPGES-2 and cytosolic PGES (cPGES) in COX-2-dependent prostaglandin E(2) (PGE(2)) formation following proteinase-activated receptor-2 (PAR2) stimulation in human lung epithelial cells. PAR2 stimulation up-regulated mPGES-1 as well as COX-2, but not mPGES-2 or cPGES, leading to PGE(2) formation. The PAR2-triggered up-regulation of mPGES-1 was suppressed by inhibitors of COX-1, cytosolic phospholipase A(2) (cPLA(2)) and MEK, but not COX-2. Finally, a selective inhibitor of mPGES-1 strongly suppressed the PAR2-evoked PGE(2) formation. PAR2 thus appears to trigger specific up-regulation of mPGES-1 that is dependent on prostanoids formed via the MEK/ERK/cPLA(2)/COX-1 pathway, being critical for PGE(2) formation.
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Affiliation(s)
- Mami Nagataki
- Division of Physiology and Pathophysiology, Kinki University School of Pharmacy, Higashi-Osaka, Japan
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Tennant GM, Wadsworth RM, Kennedy S. PAR-2 mediates increased inflammatory cell adhesion and neointima formation following vascular injury in the mouse. Atherosclerosis 2008; 198:57-64. [DOI: 10.1016/j.atherosclerosis.2007.09.043] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2007] [Revised: 09/21/2007] [Accepted: 09/27/2007] [Indexed: 11/29/2022]
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van der Merwe JQ, Hollenberg MD, MacNaughton WK. EGF receptor transactivation and MAP kinase mediate proteinase-activated receptor-2-induced chloride secretion in intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 2008; 294:G441-51. [PMID: 18032480 DOI: 10.1152/ajpgi.00303.2007] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We examined the stimulus-secretion pathways whereby proteinase-activated receptor 2 (PAR-2) stimulates Cl(-) secretion in intestinal epithelial cells. SCBN and T84 epithelial monolayers grown on Snapwell supports and mounted in modified Ussing chambers were activated by the PAR-2-activating peptides SLIGRL-NH(2) and 2-furoyl-LIGRLO-NH(2). Short-circuit current (I(sc)) was used as a measure of net electrogenic ion transport. Basolateral, but not apical, application of SLIGRL-NH(2) or 2-furoyl-LIGRLO-NH(2) caused a concentration-dependent change in I(sc) that was significantly reduced in Cl(-)-free buffer and by the intracellular Ca(2+) blockers thapsigargin and BAPTA-AM, but not by the Ca(2+) channel blocker verapamil. Inhibitors of PKA (H-89) and CFTR (glibenclamide) also significantly reduced PAR-2-stimulated Cl(-) transport. PAR-2 activation was associated with increases in cAMP and intracellular Ca(2+). Immunoblot analysis revealed increases in phosphorylation of epidermal growth factor (EGF) receptor (EGFR) tyrosine kinase, Src, Pyk2, cRaf, and ERK1/2 in response to PAR-2 activation. Pretreatment with inhibitors of cyclooxygenases (indomethacin), tyrosine kinases (genistein), EGFR (PD-153035), MEK (PD-98059 or U-0126), and Src (PP1) inhibited SLIGRL-NH(2)-induced increases in I(sc). Inhibition of Src, but not matrix metalloproteinases, reduced EGFR phosphorylation. Reduced EGFR phosphorylation paralleled the reduction in PAR-2-stimulated I(sc). We conclude that activation of basolateral, but not apical, PAR-2 induces epithelial Cl(-) secretion via cAMP- and Ca(2+)-dependent mechanisms. The secretory effect involves EGFR transactivation by Src, leading to subsequent ERK1/2 activation and increased cyclooxygenase activity.
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Affiliation(s)
- Jacques Q van der Merwe
- Inflammation Research Network, Department of Physiology, University of Calgary, Calgary, AB, Canada T2N 4N1
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Kobayashi M, Kume H, Oguma T, Makino Y, Ito Y, Shimokata K. Mast cell tryptase causes homologous desensitization of beta-adrenoceptors by Ca2+ sensitization in tracheal smooth muscle. Clin Exp Allergy 2007; 38:135-44. [PMID: 18028457 DOI: 10.1111/j.1365-2222.2007.02879.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Recent studies have revealed that in asthma, mast cells infiltrate to the smooth muscle layer and release tryptase, an enzymatic activator of protease-activated receptor 2 (PAR2). This phenomenon, mast cell myositis, is proposed as a new feature of asthma. However, little is known about the involvement of mast cell myositis in the pathophysiology of asthma. OBJECTIVE This study was designed to determine whether mast cell degranulation has any functional impact on beta-adrenoceptors via PAR2 in airway smooth muscle. Moreover, we focused on Ca(2+) signalling as a mechanism underlying alteration of smooth muscle tone and responsiveness. METHODS Isometric tension and F(340)/F(380), an indicator of the concentration of intracellular Ca(2+) ([Ca(2+)](i)), were simultaneously measured using fura-2-loaded tissues isolated from guinea-pig tracheal smooth muscle. RESULTS Tryptase (1-100 nm) caused tension with elevated F(340)/F(380), and after exposure to tryptase for 15 min the inhibitory effect of isoprenaline (ISO) against methacholine was attenuated without elevating F(340)/F(380) in a concentration-dependent manner. Tryptase (<1 nm) had a modest effect on tension, but prolonged treatment (</=120 min) with 0.1 nm tryptase also reduced the effects of ISO in a time-dependent manner. When tissues were incubated with tryptase in the presence of Y-27632, a Rho-kinase inhibitor, reduced responsiveness to ISO by tryptase was reversed without affecting F(340)/F(380). In contrast, pre-treatment with SKF96365, a non-selective inhibitor of Ca(2+) channels, did not antagonize the effect of tryptase. Moreover, pre-treatment with SLIGKV-NH(2), a non-enzymatic activator of PAR2, resulted in a loss of beta-adrenergic efficacy, similar to tryptase. The effect of cAMP-related agents bypassing beta-adrenoceptors was not attenuated after exposure to tryptase. CONCLUSION In mast cell myositis, tryptase released from mast cells acts on airway smooth muscle, leading to homologous beta-adrenergic desensitization mediated by [Ca(2+)](i)-independent mechanisms via PAR2 activation.
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Affiliation(s)
- M Kobayashi
- Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
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14
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Saleh SM, Mann TS, Peters T, Betts RJ, Henry PJ. Influence of dexamethasone on protease-activated receptor 2-mediated responses in the airways. J Pharmacol Exp Ther 2007; 324:622-30. [PMID: 18003863 DOI: 10.1124/jpet.107.132753] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Stimulants of protease-activated receptor (PAR)(2) promote the generation of the bronchoprotective prostanoid prostaglandin (PG) E(2) by airway epithelial cells. In contrast, glucocorticoids reduce the levels of PGE(2) in airway epithelial cell cultures by concomitantly inhibiting pathways required for PGE(2) synthesis and facilitating pathways involved in PGE(2) inactivation. The aim of this study was to determine whether glucocorticoids inhibited PAR(2)-mediated, PGE(2)-dependent responses in epithelial cell cultures, in intact airway preparations, and in whole animals. In cultures of A549 cells, a PAR(2)-activating peptide SLI-GRL-NH(2) produced concentration and time-dependent increases in PGE(2) levels, which were significantly enhanced after exposure to lipopolysaccharide (LPS). However, SLIGRL-NH(2)-induced increases in PGE(2) levels were abolished by pretreatment of cells with the glucocorticoid, dexamethasone. In mouse isolated tracheal preparations, SLIGRL-NH(2) and PGE(2) induced concentration-dependent relaxation responses that were unaffected by dexamethasone, irrespective of whether dexamethasone exposure occurred in vitro or in vivo. Intranasal administration of LPS produced a pronounced increase in the numbers of neutrophils recovered from the bronchoalveolar lavage fluid of BALB/c mice. Numbers of recovered neutrophils were 40 to 60% lower in mice that received f-LIGRL-NH(2) (PAR(2)-activating peptide, 30 microg intranasally), PGE(2) (10 mugintranasally), or dexamethasone (1 mg/kg i.p.). In the combined presence of dexamethasone and f-LIGRL-NH(2) or dexamethasone and PGE(2), the number of neutrophils was suppressed further (80-83% lower). Thus, although dexamethasone abolished PAR(2)-mediated generation of PGE(2) in A549 cells, neither the smooth muscle relaxant nor the anti-inflammatory effects of PAR(2)-activating peptides (and PGE(2)) were diminished by in vitro or in vivo exposure to dexamethasone.
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Affiliation(s)
- Sham Mohd Saleh
- School of Medicine and Pharmacology, University of Western Australia, Stirling Highway, Nedlands, Australia
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15
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Carrier E, Brochu I, de Brum-Fernandes AJ, D'Orléans-Juste P. The inducible nitric-oxide synthase modulates endothelin-1-dependent release of prostacyclin and inhibition of platelet aggregation ex vivo in the mouse. J Pharmacol Exp Ther 2007; 323:972-8. [PMID: 17885093 DOI: 10.1124/jpet.107.125690] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nitric oxide and other reactive oxygen species generated by nitric-oxide synthases (NOS) modulate, among several other cellular responses, the production of eicosanoids and platelet aggregation. The roles of specific NOS in these two phenomena remain to be determined. Thus, the present study assessed whether inducible NOS (iNOS) and endothelial NOS (eNOS) modulate in a similar manner the production of eicosanoids and platelet aggregation. Mice knocked out for eNOS (eNOS-/-) or iNOS (iNOS-/-) and their wild-type (WT) congeners were used to analyze agonist-induced increases in plasma levels of eicosanoids as well as inhibition of platelet aggregation ex vivo. Systemically administered endothelin-1 (ET-1) triggered an increase in plasma levels of 6-keto prostaglandin F(1alpha) (6-keto PGF(1alpha)) in WT and eNOS-/- but not in iNOS-/- mice. ET-1 (0.01-1 nmol/kg) also induced a dose-dependent inhibition of platelet aggregation in WT and eNOS-/- but not in iNOS-/- mice. Another agonist, bradykinin (10 nmol/kg), triggered the release of 6-keto PGF(1alpha) and inhibited platelet aggregation in all strains of mice studied. In addition, ADP-induced platelet aggregation in vitro was similarly reduced by iloprost (100 nM) in iNOS-/- mice and WT congeners. In another series of experiments, ET-1 (0.1 nmol/kg) significantly increased 8-isoprostane plasma levels in WT but not in iNOS-/- mice. Finally, a 3-week treatment with anti-oxidants inhibited the capacity of ET-1 to significantly increase plasma 6-keto PGF(1alpha) in WT mice. We show for the first time that iNOS is involved in the control of ET-1-induced prostacyclin release and related inhibition of platelet aggregation in the murine model.
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Affiliation(s)
- Emilie Carrier
- Department of Pharmacology, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
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16
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Moriyuki K, Nagataki M, Sekiguchi F, Nishikawa H, Kawabata A. Signal transduction for formation/release of interleukin-8 caused by a PAR2-activating peptide in human lung epithelial cells. ACTA ACUST UNITED AC 2007; 145:42-8. [PMID: 17854923 DOI: 10.1016/j.regpep.2007.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Proteinase-activated receptor-2 (PAR2) plays a dual role in the respiratory system, being pro- and anti-inflammatory. In human lung epithelial cells (A549), PAR2 activation causes release of interleukin-8 (IL-8) in addition to prostaglandin E(2) (PGE(2)). In the present study, we thus investigated PAR2-triggered signal transduction pathways causing IL-8 formation in A549 cells. SLIGRL-NH(2), a PAR2-activating peptide, but not LSIGRL-NH(2), a scrambled peptide, elicited release of IL-8 from A549 cells for 18 h, as measured by the ELISA method, an effect being suppressed by inhibitors of MEK, JNK, EGF receptor-tyrosine kinase (EGFR-TK), Src, pan-tyrosine kinases and protein kinase C, but not p38 MAP kinase or cyclooxygenase. SLIGRL-NH(2) also up-regulated IL-8 at protein and mRNA levels, as determined by Western blotting and RT-PCR, respectively. The PAR2-triggered up-regulation of IL-8 protein and mRNA was blocked by an inhibitor of MEK, but not clearly by inhibitors of JNK and EGFR-TK. SLIGRL-NH(2) actually phosphorylated JNK as well as ERK, the JNK activation being resistant to inhibitors of Src, pan-tyrosine kinases, protein kinase C and EGFR-TK. Our data suggest that PAR2-triggered IL-8 formation involves transcriptional up-regulation of IL-8 via the MEK-ERK pathway, while the JNK and EGF receptor pathways might rather contribute to a post-transcriptional process for the release of IL-8.
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Affiliation(s)
- Kazumi Moriyuki
- Division of Physiology and Pathophysiology, School of Pharmacy, Kinki University, Higashi-Osaka 577-8502, Japan
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17
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Kubo S, Doe I, Kurokawa Y, Kawabata A. Hydrogen sulfide causes relaxation in mouse bronchial smooth muscle. J Pharmacol Sci 2007; 104:392-6. [PMID: 17675793 DOI: 10.1254/jphs.sc0070199] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We investigated the effects of NaHS, a hydrogen sulfide (H(2)S) donor, on the tension of isolated mouse and guinea-pig bronchial rings. NaHS at 0.01 - 10 mM had no effect on the tone of those preparations without precontraction. When the preparation was precontracted with carbachol, NaHS at 0.1 - 3 mM strongly relaxed the mouse rings, but produced only slight relaxation in the guinea-pig rings. The NaHS-induced relaxation in the mouse bronchus was resistant to inhibitors of ATP-sensitive K(+) channels, soluble guanylyl cyclase, cyclooxygenase (COX)-1 or COX-2, and antagonists of tachykinin receptors. Thus, NaHS evokes bronchodilation in mice, suggesting a possible role for H(2)S in the respiratory system.
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Affiliation(s)
- Satoko Kubo
- Division of Pharmacology and Pathophysiology, Kinki University School of Pharmacy, Higashi-Osaka, Japan
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18
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Kubo S, Ishiki T, Doe I, Sekiguchi F, Nishikawa H, Kawai K, Matsui H, Kawabata A. Distinct activity of peptide mimetic intracellular ligands (pepducins) for proteinase-activated receptor-1 in multiple cells/tissues. Ann N Y Acad Sci 2007; 1091:445-59. [PMID: 17341635 DOI: 10.1196/annals.1378.087] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Proteinase-activated receptor-1 (PAR1), a G protein-coupled receptor (GPCR) for thrombin, can be activated not only by PAR1-activating peptides (PAR1APs) based on the N-terminal cryptic tethered ligand sequence but also by an N-palmitoylated (Pal) peptide, Pal-RCLSSSAVANRSKKSRALF-amide (P1pal-19), based on the intracellular loop 3 of PAR1, designated pepducin, in human platelets or PAR1-transfected cells. The present article evaluated the actions of P1pal-19 and also the shorter peptide, Pal-RCLSSSAVANRS-amide (P1pal-12), known as a possible PAR1 antagonist, in multiple cells/tissues that naturally express PAR1. P1pal-19 as well as a PAR1AP, TFLLR-amide, evoked cytosolic Ca(2+) mobilization in cultured human lung epithelial cells (A549) and rat gastric mucosal epithelial cells (RGM1). P1pal-19 and TFLLR-amide, but not a PAR2-activating peptide, SLIGRL-amide, caused delayed prostaglandin E(2) formation in RGM1 cells. P1pal-19, like TFLLR-amide, produced endothelial NO-dependent relaxation in rat aorta and epithelial prostanoid-dependent relaxation in mouse bronchus. The P1pal-19-induced relaxation remained constant even after desensitization of PAR1 with TFLLR-amide in either tissue. P1pal-19 failed to mimic the contractile effects of TFLLR-amide in the endothelium-denuded preparations of rat aorta or superior mesenteric artery and the rat gastric longitudinal smooth muscle strips. P1pal-12 partially inhibited the vasorelaxation caused by TFLLR-amide and P1pal-19, but not SLIGRL-amide, in the rat aorta. Our data thus indicate that P1pal-19 is capable of mimicking the effects of PAR1APs in the endothelial and epithelial, but not smooth muscle, cells/tissues, and suggest that P1pal-12 may act as a PAR1 antagonist in the vascular endothelium.
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Affiliation(s)
- Satoko Kubo
- Division of Physiology and Pathophysiology, School of Pharmaceutical Sciences, Kinki University, 3-4-1 Kowakae, Higashi-Osaka 577-8502, Japan
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19
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Freund-Michel V, Frossard N. Inflammatory conditions increase expression of protease-activated receptor-2 by human airway smooth muscle cells in culture. Fundam Clin Pharmacol 2006; 20:351-7. [PMID: 16867018 DOI: 10.1111/j.1472-8206.2006.00418.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The protease-activated receptor-2 (PAR-2) has been implicated in airway inflammation and bronchial hyperresponsiveness. We wondered whether inflammatory conditions may upregulate PAR-2 expression by the human airway smooth muscle. To do so, we treated human airway smooth muscle cells (HASMC) in primary culture with interleukin-1beta (IL-1beta), a pro-inflammatory and asthma-associated cytokine. Cells were starved for 24 h and incubated with or without IL-1beta. Online fluorescent polymerase chain reaction after reverse transcription quantified PAR-2 mRNA, and Western blotting measured PAR-2 protein expression. PAR-2 was constitutively expressed by HASMC in primary culture, and IL-1beta (10 U/mL) time dependently elevated PAR-2 mRNA with a maximum of 4.7-fold after 1.5 h (P < 0.01), and PAR-2 protein expression with a maximum of 1.5-fold after 24 h (P < 0.01). The concentration dependence of the IL-1beta effect (0.1-30 U/mL) confirmed a maximal increase of PAR-2 expression at 10 U/mL. Our study clearly shows that IL-1beta upregulates PAR-2 mRNA and protein expression by HASMC in culture. This increased expression of PAR-2 in inflammatory conditions may have functional consequences in the bronchial dysfunction of asthmatic airways.
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Affiliation(s)
- Véronique Freund-Michel
- EA 3771 Inflammation and Environment in Asthma, Faculté de Pharmacie, Université Louis Pasteur-Strasbourg I, Illkirch, France.
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20
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Xiang Y, Masuko-Hongo K, Sekine T, Nakamura H, Yudoh K, Nishioka K, Kato T. Expression of proteinase-activated receptors (PAR)-2 in articular chondrocytes is modulated by IL-1beta, TNF-alpha and TGF-beta. Osteoarthritis Cartilage 2006; 14:1163-73. [PMID: 16757188 DOI: 10.1016/j.joca.2006.04.015] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2005] [Accepted: 04/18/2006] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To investigate the modulation of expression of proteinase-activated receptor-2 (PAR-2) in articular chondrocytes by inflammatory cytokines. DESIGN Articular synovium and cartilage tissues were collected from eight patients with osteoarthritis (OA), and three patients without arthropathy ("normal"). Chondrocytes were stimulated with interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha or transforming growth factor (TGF)-beta1. The expression of PAR-2 was detected using reverse transcriptase-polymerase chain reaction (PCR), Western blotting and immunofluorescence. Quantitative PCR was performed to assess the expression levels of PAR-2 messenger RNA (mRNA). RESULTS The expression of PAR-2 mRNA was demonstrated in both OA and normal chondrocytes as well as in synovial fibroblasts. However, the level of PAR-2 in OA chondrocytes was much higher than in normal chondrocytes. Long-term culture revealed that PAR-2 mRNA expression was maintained up to three passages in OA but not in normal chondrocytes. IL-1beta and TNF-alpha both upregulated PAR-2 expression in normal and OA chondrocytes. In contrast, TGF-beta1 significantly decreased expression of PAR-2 in OA chondrocytes but increased PAR-2 in normal chondrocytes. CONCLUSIONS Overexpression of PAR-2 in OA chondrocytes is upregulated by proinflammatory cytokines IL-1beta and TNF-alpha, and down-regulated by regulatory cytokine TGF-beta1. PAR-2 may be involved in the pathogenesis of OA.
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Affiliation(s)
- Y Xiang
- Department of Bioregulation and Proteomics, Institute of Medical Science, St. Marianna University School of Medicine, Kawasaki, Japan
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21
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Kawabata A. [Proteinase-activated receptors and gastrointestinal functions]. Nihon Yakurigaku Zasshi 2006; 128:82-7. [PMID: 16943642 DOI: 10.1254/fpj.128.82] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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22
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Henry PJ. The protease-activated receptor2 (PAR2)-prostaglandin E2-prostanoid EP receptor axis: a potential bronchoprotective unit in the respiratory tract? Eur J Pharmacol 2006; 533:156-70. [PMID: 16483565 DOI: 10.1016/j.ejphar.2005.12.051] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2005] [Indexed: 01/12/2023]
Abstract
Protease-activated receptor2 (PAR2) is a subtype of G protein-coupled receptor that is widely expressed within the respiratory tract. Stimulation of PAR2 by proteases such as trypsin and tryptase, or by small peptidic activators induces a complex array of effects within the airways. One such PAR2-mediated effect by basal airway epithelial cells is the generation of prostaglandin E2. Prostaglandin E2 produces a raft of anti-inflammatory effects within the airways, principally through the activation of the prostanoid EP2 and EP3 receptor subtypes. This article reviews the PAR2-prostaglandin E2-prostanoid EP receptor axis and discusses approaches through which its activation may provide beneficial effects in respiratory disease.
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MESH Headings
- Animals
- Anti-Inflammatory Agents/pharmacology
- Anti-Inflammatory Agents/therapeutic use
- Dinoprostone/metabolism
- Disease Models, Animal
- Humans
- Ligands
- Pneumonia/metabolism
- Pneumonia/prevention & control
- Receptor, PAR-2/drug effects
- Receptor, PAR-2/metabolism
- Receptors, Prostaglandin E/drug effects
- Receptors, Prostaglandin E/metabolism
- Receptors, Prostaglandin E, EP1 Subtype
- Receptors, Prostaglandin E, EP2 Subtype
- Receptors, Prostaglandin E, EP3 Subtype
- Respiratory Mucosa/drug effects
- Respiratory Mucosa/metabolism
- Respiratory System/drug effects
- Respiratory System/metabolism
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Affiliation(s)
- Peter J Henry
- School of Medicine and Pharmacology, University of Western Australia, Stirling Highway, Nedlands, Western Australia, 6009, Australia.
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23
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Balzary RW, Cocks TM. Lipopolysaccharide Induces Epithelium- and Prostaglandin E2-Dependent Relaxation of Mouse Isolated Trachea through Activation of Cyclooxygenase (COX)-1 and COX-2. J Pharmacol Exp Ther 2006; 317:806-12. [PMID: 16464966 DOI: 10.1124/jpet.105.097634] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Lipopolysaccharide (LPS), a Toll-like receptor (TLR) 4 agonist, causes airway hyperreactivity through nuclear factor-kappaB (NF-kappaB). Because NF-kappaB induces cyclooxygenase-2 (COX-2) to increase synthesis of prostaglandins (PGs), including the potent airway anti-inflammatory and smooth muscle relaxant PGE(2), we investigated whether LPS causes short-term PGE(2)-dependent relaxation of mouse isolated trachea. In rings of trachea contracted submaximally with carbachol, LPS caused slowly developing, epithelium-dependent relaxations that reached a maximum within 60 min. Fluorescence immunohistochemistry revealed TLR4-like immunoreactivity localized predominantly to the epithelium. The LPS antagonist polymixin B; the nonselective COX inhibitor indomethacin; the selective COX-1 and COX-2 inhibitors 5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-(trifluoromethyl)-1H-pyrazole (SC560) and 4-[5-(4-chlorophenyl)-1-(trifluoromethyl)-1H-pyrazol-1-yl]-benzenesulfonamide (SC236), respectively; the transcription inhibitor actinomycin D; the translation inhibitor cycloheximide; the p38 mitogen-activated protein kinase (p38 MAPK) inhibitor 4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)-1H-imadazole (SB203580); and a combination of the mixed DP/EP1/EP2 receptor antagonist 6-isopropoxy-9-xanthone-2-carboxylic acid (AH6809) and the EP4 receptor antagonist 4'-[3-butyl-5-oxo-1-(2-trifluoromethyl-phenyl)-1-5-dihydro-[1,2,4]triazol-4-ylmethyl]-biphenyl-2-sulfonic acid (3-methyl-thiophene-2-carbonyl)-amide (L-161982) all abolished relaxation to LPS, giving instead slowly developing, small contractions over 60 min. The cytosolic phospholipase A(2) (cPLA(2)) inhibitor 1,1,1-trifluoro-6Z,9Z, 12Z,15Z-heneicosateraen-2-one significantly (p < 0.05) inhibited the relaxation to LPS, whereas the NF-kappaB proteasomal inhibitor Z-Leu-Leu-Leu-aldehyde (MG-132) had no affect on the relaxation in the first 20 min, after which it reversed the response to a contraction. In conclusion, our data indicate that LPS activates airway epithelial TLR4 to cause release of PGE(2) and subsequent EP2 and EP4 receptor-dependent smooth muscle relaxation. Activation of both COX-1 and COX-2 seems to be essential for this novel response to LPS, which also involves cPLA(2), p38 MAPK, NF-kappaB, and an unidentified NF-kappaB-independent, labile regulatory protein.
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Affiliation(s)
- Rowan W Balzary
- Department of Pharmacology, The University of Melbourne, Parkville, Australia
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24
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Sekiguchi F, Hasegawa N, Inoshita K, Yonezawa D, Inoi N, Kanke T, Saito N, Kawabata A. Mechanisms for modulation of mouse gastrointestinal motility by proteinase-activated receptor (PAR)-1 and -2 in vitro. Life Sci 2006; 78:950-7. [PMID: 16188279 DOI: 10.1016/j.lfs.2005.06.035] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2005] [Accepted: 06/01/2005] [Indexed: 11/25/2022]
Abstract
Proteinase-activated receptor (PAR)-1 or -2 modulates gastrointestinal transit in vivo. To clarify the underlying mechanisms, we characterized contraction/relaxation caused by TFLLR-NH2 and SLIGRL-NH2, PAR-1- and -2-activating peptides, respectively, in gastric and small intestinal (duodenal, jejunal and ileal) smooth muscle isolated from wild-type and PAR-2-knockout mice. Either SLIGRL-NH2 or TFLLR-NH2 caused both relaxation and contraction in the gastrointestinal preparations from wild-type animals. Apamin, a K+ channel inhibitor, tended to enhance the peptide-evoked contraction in some of the gastrointestinal preparations, whereas it inhibited relaxation responses to either peptide completely in the stomach, but only partially in the small intestine. Indomethacin reduced the contraction caused by SLIGRL-NH2 or TFLLR-NH2 in both gastric and ileal preparations, but unaffected apamin-insensitive relaxant effect of either peptide in ileal preparations. Repeated treatment with capsaicin suppressed the contractile effect of either peptide in the stomach, but not clearly in the ileum, whereas it enhanced the apamin-insensitive relaxant effect in ileal preparations. In any gastrointestinal preparations from PAR-2-knockout mice, SLIGRL-NH2 produced no responses. Thus, the inhibitory component in tension modulation by PAR-1 and -2 involves both apamin-sensitive and -insensitive mechanisms in the small intestine, but is predominantly attributable to the former mechanism in the stomach. The excitatory component in the PAR-1 and -2 modulation may be mediated, in part, by activation of capsaicin-sensitive sensory nerves and/or endogenous prostaglandin formation. Our study thus clarifies the multiple mechanisms for gastrointestinal motility modulation by PAR-1 and -2, and also provides ultimate evidence for involvement of PAR-2.
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MESH Headings
- Animals
- Anti-Inflammatory Agents, Non-Steroidal/pharmacology
- Apamin/pharmacology
- Calcium Channel Blockers/pharmacology
- Capsaicin/pharmacology
- Female
- Gastrointestinal Motility/drug effects
- In Vitro Techniques
- Indomethacin/pharmacology
- Intestines/drug effects
- Isometric Contraction/drug effects
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle Relaxation/drug effects
- Neurons, Afferent/drug effects
- Oligopeptides/pharmacology
- Potassium Channels/drug effects
- Potassium Channels/metabolism
- Prostaglandins/pharmacology
- Receptor, PAR-1/agonists
- Receptor, PAR-1/antagonists & inhibitors
- Receptor, PAR-1/drug effects
- Receptor, PAR-2/agonists
- Receptor, PAR-2/antagonists & inhibitors
- Receptor, PAR-2/drug effects
- Reverse Transcriptase Polymerase Chain Reaction
- Stomach/drug effects
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Affiliation(s)
- Fumiko Sekiguchi
- Division of Physiology and Pathophysiology, School of Pharmaceutical Sciences, Kinki University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, Japan
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25
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Freerksen N, Betancourt A, Maul H, Wentz M, Orise P, Günter HH, Sohn C, Vedernikov Y, Saade G, Garfield R. PAR-2 activating peptide-induced stimulation of pregnant rat myometrium contractile activity partly involves the other membrane receptors. Eur J Obstet Gynecol Reprod Biol 2005; 130:51-9. [PMID: 16386349 DOI: 10.1016/j.ejogrb.2005.11.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2004] [Revised: 11/18/2005] [Accepted: 11/21/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To study if spontaneous contractions augmented by proteinase-activated receptor-2 (PAR-2)-activating peptide serine-leucine-isoleucine-glycine-arginine-leucine (SLIGRL) involve coactivation of membrane chemoceptors and are associated with expression of PAR-2 mRNA in non-pregnant and pregnant rat myometrium. MATERIALS AND METHODS Non-pregnant, mid-pregnant, and late pregnant rat uterine horn and small intestine segments were snap-frozen in liquid nitrogen to determine PAR-2 mRNA levels by real time polymerase chain reaction (PCR). Uterine rings were used for isometric tension recording. Effect of SLIGRL (0.1 mM) on spontaneous contractions before and after exposure to ibuprofen (cyclooxygenase inhibitor, 1.0 microM), SQ-29548 (thromboxane A(2) receptor inhibitor, 1.0 microM), ketotifen (histamine 1 receptor inhibitor, 10 microM), WEB-2170BS (platelet-activating factor (PAF) receptor inhibitor, 10 microM), atropine (muscarinic receptor inhibitor, 0.1 microM), or ketanserin (serotonin receptor inhibitor, 10 microM) were compared. Paired t-test and one-way ANOVA followed by Dunnett's or Newman-Keuls post hoc tests were used for statistical analysis when appropriate. SIGNIFICANCE P<0.05. RESULTS The agents did not significantly affect time-associated decay in spontaneous contractile activity in any group of the tissues. Activation of spontaneous contractions induced by SLIGRL in non-pregnant rat myometrium did not involve coactivation of membrane chemoceptors, while in mid-pregnant rat myometrium coactivation of prostanoid, histamine, and serotonin receptors and in late pregnant rat myometrium coactivation of thromboxane receptors was noted. Expression of PAR-2 mRNA was similar in non-pregnant, mid-pregnant, and late pregnant rat myometrium. CONCLUSIONS Expression of PAR-2 in rat myometrium is not dependent on gestational age. Stimulation of PAR-2 is associated with production/release of cyclooxygenase pathway product(s) activating thromboxane/prostaglandin H2 receptors, partial involvement of histamine H1 receptors and serotonin receptors in midpregnancy and thromboxane A2/prostaglandin H2 receptors in late pregnancy.
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MESH Headings
- Animals
- Atropine/pharmacology
- Bridged Bicyclo Compounds, Heterocyclic
- Fatty Acids, Unsaturated
- Female
- Hydrazines/pharmacology
- Ibuprofen/pharmacology
- In Vitro Techniques
- Ketanserin/pharmacology
- Ketotifen/pharmacology
- Metabolic Networks and Pathways/physiology
- Myometrium/drug effects
- Oligopeptides/physiology
- Platelet Membrane Glycoproteins/antagonists & inhibitors
- Pregnancy
- Prostaglandin-Endoperoxide Synthases/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptor, PAR-2/antagonists & inhibitors
- Receptor, PAR-2/drug effects
- Receptor, PAR-2/metabolism
- Receptors, G-Protein-Coupled/antagonists & inhibitors
- Receptors, Histamine H1/drug effects
- Receptors, Histamine H1/physiology
- Receptors, Serotonin/drug effects
- Receptors, Serotonin/physiology
- Receptors, Thromboxane A2, Prostaglandin H2/drug effects
- Receptors, Thromboxane A2, Prostaglandin H2/physiology
- Uterine Contraction/drug effects
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Affiliation(s)
- Nele Freerksen
- Medizinische Hochschule Hannover, Zentrum für Frauenheilkunde, Abteilung I für Pränatalmedizin, Allgemeine Gynäkologie und Geburtshilfe, Hannover, Germany
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26
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Kawao N, Nagataki M, Nagasawa K, Kubo S, Cushing K, Wada T, Sekiguchi F, Ichida S, Hollenberg MD, MacNaughton WK, Nishikawa H, Kawabata A. Signal transduction for proteinase-activated receptor-2-triggered prostaglandin E2 formation in human lung epithelial cells. J Pharmacol Exp Ther 2005; 315:576-89. [PMID: 16120814 DOI: 10.1124/jpet.105.089490] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated proteinase-activated receptor-2 (PAR(2))-triggered signal transduction pathways causing increased prostaglandin E(2) (PGE(2)) formation in human lung-derived A549 epithelial cells. The PAR(2) agonist, SLIGRL-NH(2) (Ser-Leu-Ile-Gly-Arg-Leu-amide), evoked immediate cytosolic Ca(2+) mobilization and delayed (0.5-3 h) PGE(2) formation. The PAR(2)-triggered PGE(2) formation was attenuated by inhibition of the following signal pathway enzymes: cyclooxygenases 1 and 2 (COX-1 and COX-2, respectively), cytosolic Ca(2+)-dependent phospholipase A(2) (cPLA(2)), the mitogen-activated protein kinases (MAPKs), mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK)-extracellular signal-regulated kinase (ERK) and p38 MAPK, Src family tyrosine kinase, epidermal growth factor (EGF) receptor tyrosine kinase (EGFRK), and protein kinase C (PKC), but not by inhibition of matrix metalloproteinases. SLIGRL-NH(2) caused prompt (5 min) and transient ERK phosphorylation, blocked in part by inhibitors of PKC and tyrosine kinases but not by an EGFRK inhibitor. SLIGRL-NH(2) also evoked a relatively delayed (15 min) and persistent (30 min) phosphorylation of p38 MAPK, blocked by inhibitors of Src and EGFRK but not by inhibitors of COX-1 or COX-2. SLIGRL-NH(2) elicited a Src inhibitor-blocked prompt (5 min) and transient phosphorylation of the EGFRK. SLIGRL-NH(2) up-regulated COX-2 protein and/or mRNA levels that were blocked by inhibition of p38 MAPK, EGFRK, Src, and COX-2 but not MEK-ERK. SLIGRL-NH(2) also caused COX-1-dependent up-regulation of microsomal PGE synthase-1 (mPGES-1). We conclude that PAR(2)-triggered PGE(2) formation in A549 cells involves a coordinated up-regulation of COX-2 and mPGES-1 involving cPLA(2), increased cytosolic Ca(2+), PKC, Src, MEK-ERK, p38 MAPK, Src-mediated EGF receptor trans-activation, and also metabolic products of both COX-1 and COX-2.
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Affiliation(s)
- Naoyuki Kawao
- Division of Physiology and Pathophysiology, School of Pharmaceutical Sciences, Kinki University, Higashi-Osaka, Japan
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27
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De Campo BA, Henry PJ. Stimulation of protease-activated receptor-2 inhibits airway eosinophilia, hyperresponsiveness and bronchoconstriction in a murine model of allergic inflammation. Br J Pharmacol 2005; 144:1100-8. [PMID: 15700024 PMCID: PMC1576095 DOI: 10.1038/sj.bjp.0706150] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. An emerging body of evidence indicates that PGE(2) has a privileged anti-inflammatory role within the airways. Stimulants of protease-activated receptor-2 (PAR(2)) inhibit airway smooth muscle tone in vitro and in vivo predominantly via cyclooxygenase (COX)-dependent generation of prostaglandin E(2) (PGE(2)). Thus, the current study tested the hypothesis that PAR(2)-induced generation of PGE(2) inhibits the development of allergic airways inflammation and hyperresponsiveness. 2. Bronchoalveolar lavage (BAL) fluid recovered from ovalbumin (OVA)-sensitised and -challenged (allergic) mice contained elevated numbers of eosinophils, which peaked at 48 h postchallenge. Intranasal (i.n.) administration of a PAR(2)-activating peptide (PAR(2)-AP) SLIGRL (25 mg kg(-1), at the time of OVA challenge) caused a 70% reduction in the numbers of BAL eosinophils (compared to the scrambled peptide LSIGRL, 25 mg kg(-1)). 3. Pretreatment of allergic mice with either indomethacin (1 mg kg(-1), dual COX inhibitor) or nimesulide (3 mg kg(-1), COX-2-selective inhibitor) blocked SLIGRL-induced reductions in BAL eosinophils. 4. I.n. SLIGRL, but not LSIGRL, inhibited the development of antigen-induced airways hyperresponsiveness. The inhibitory effect of SLIGRL was blocked by indomethacin. 5. Exposure of isolated tracheal preparations from allergic mice to 100 microM SLIGRL was associated with a 5.0-fold increase in PGE(2) levels (P<0.05, compared to 100 microM LSIGRL). SLIGRL induced similar increases in PGE(2) levels in control mice (OVA-sensitised, saline-challenged). 6. I.n. administration of PGE(2) (0.15 mg kg(-1)) to allergic mice significantly inhibited eosinophilia and airways hyperresponsiveness to methacholine. 7. In anaesthetised, ventilated allergic mice, SLIGRL (5 mg kg(-1), i.v.) inhibited methacholine-induced increases in airways resistance. Consistent with this bronchodilator effect, SLIGRL induced pronounced relaxation responses in isolated tracheal preparations obtained from allergic mice. LSIGRL did not inhibit bronchomotor tone in either of these in vivo or in vitro experiments. 8. In summary, a PAR(2)-AP SLIGRL inhibited the development of airway eosinophilia and hyperresponsiveness in allergic mice through a COX-dependent pathway involving COX-2-mediated generation of the anti-inflammatory mediator PGE(2). SLIGRL also displayed bronchodilator activity in allergic mice. These studies support the concept that PAR(2) exerts predominantly bronchoprotective actions within allergic murine airways.
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Affiliation(s)
- Benjamin A De Campo
- Respiratory Pharmacology Group, School of Medicine and Pharmacology, University of Western Australia, 35 Stirling Hwy, Nedlands, Australia
- Western Australian Institute for Medical Research, University of Western Australia, Nedlands, Western Australia 6009, Australia
| | - Peter J Henry
- Respiratory Pharmacology Group, School of Medicine and Pharmacology, University of Western Australia, 35 Stirling Hwy, Nedlands, Australia
- Western Australian Institute for Medical Research, University of Western Australia, Nedlands, Western Australia 6009, Australia
- Author for correspondence:
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28
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Henry PJ, D'Aprile A, Self G, Hong T, Mann TS. Inhibitors of Prostaglandin Transport and Metabolism Augment Protease-Activated Receptor-2-Mediated Increases in Prostaglandin E2 Levels and Smooth Muscle Relaxation in Mouse Isolated Trachea. J Pharmacol Exp Ther 2005; 314:995-1001. [PMID: 15937152 DOI: 10.1124/jpet.105.086124] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Stimulants of protease-activated receptor-2 (PAR(2)), such as Ser-Leu-Ile-Gly-Arg-Leu-NH(2) (SLIGRL), cause airway smooth muscle relaxation via the release of the bronchodilatory prostanoid prostaglandin E(2) (PGE(2)). The principal aim of the current study was to determine whether compounds that inhibit PGE(2) reuptake by the prostaglandin transporter [bromocresol green and U46619 (9,11-dideoxy-9alpha,11alpha-methanoepoxy PGF2alpha) and PGE(2) metabolism by 15-hydroxyprostaglandin dehydrogenase (thiazolidenedione compounds rosiglitazone and ciglitazone) significantly enhanced the capacity of SLIGRL to elevate PGE(2) levels and produce relaxation in isolated segments of upper and lower mouse trachea. SLIGRL produced concentration-dependent increases in PGE(2) levels and smooth muscle relaxation, although both effects were significantly greater in lower tracheal segments than in upper tracheal segments. SLIGRL-induced increases in PGE(2) levels were significantly enhanced in the presence of ciglitazone and rosiglitazone, and these effects were not inhibited by GW9662 (2-chloro-5-nitrobenzanilide), a peroxisome proliferator-activated receptor-gamma antagonist. SLI-GRL-induced relaxation responses were also significantly enhanced by ciglitazone and rosiglitazone, whereas responses to isoprenaline, a PGE(2)-independent smooth muscle relaxant, were unaltered. Ciglitazone and rosiglitazone alone produced concentration-dependent increases in PGE(2) levels and smooth muscle relaxation, and these responses were inhibited by indomethacin, a cyclooxygenase inhibitor. Bromocresol green, an inhibitor of prostaglandin transport, significantly enhanced SLIGRL-induced increases in PGE(2) levels and relaxation. Immunohistochemical staining for 15-hydroxyprostaglandin dehydrogenase was relatively intense over airway smooth muscle, as was staining for the prostaglandin transporter over both airway smooth muscle and epithelium. In summary, inhibitors of PGE(2) reuptake and metabolism significantly potentiate PAR(2)-mediated increases in PGE(2) levels and smooth muscle relaxation in murine-isolated airways.
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Affiliation(s)
- Peter J Henry
- School of Medicine and Pharmacology, University of Western Australia, Nedlands.
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29
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Kunzelmann K, Sun J, Markovich D, König J, Mürle B, Mall M, Schreiber R. Control of ion transport in mammalian airways by protease activated receptors type 2 (PAR-2). FASEB J 2005; 19:969-70. [PMID: 15809358 DOI: 10.1096/fj.04-2469fje] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Protease-activated receptors (PARs) are widely distributed in human airways. They couple to G- proteins and are activated after proteolytic cleavage of the N terminus of the receptor. Evidence is growing that PAR subtype 2 plays a pivotal role in inflammatory airway diseases, such as allergic asthma or bronchitis. However, nothing is known about the effects of PAR-2 on electrolyte transport in the native airways. PAR-2 is expressed in airway epithelial cells, where they are activated by mast cell tryptase, neutrophil proteinase 3, or trypsin. Recent studies produced conflicting results about the functional consequence of PAR-2 stimulation. Here we report that stimulation of PAR-2 receptors in mouse and human airways leads to a change in electrolyte transport and a shift from absorption to secretion. Although PAR-2 appears to be expressed on both sides of the epithelium, only basolateral stimulation results in inhibition of amiloride sensitive Na+ conductance and stimulation of both luminal Cl- channels and basolateral K+ channels. The present data indicate that these changes occur through activation of phospholipase C and increase in intracellular Ca2+, which activates basolateral SK4 K+ channels and luminal Ca2+-dependent Cl- channels. In addition, the present data suggest a PAR-2 mediated release of prostaglandin E2, which may contribute to the secretory response. In conclusion, these results provide further evidence for a role of PAR-2 in inflammatory airway disease: stimulation of these receptors may cause accumulation of airway surface liquid, which, however, may help to flush noxious stimuli away from the affected airways.
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Affiliation(s)
- Karl Kunzelmann
- Institut für Physiologie, Universität Regensburg, Regensburg, Germany.
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30
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Kawabata A, Kawao N. Physiology and pathophysiology of proteinase-activated receptors (PARs): PARs in the respiratory system: cellular signaling and physiological/pathological roles. J Pharmacol Sci 2005; 97:20-4. [PMID: 15655298 DOI: 10.1254/jphs.fmj04005x4] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Proteinase-activated receptors (PARs), a family of G protein-coupled receptors, are widely distributed in the mammalian body, playing a variety of physiological/pathophysiological roles. In the respiratory systems, PARs, particularly PAR-2 and PAR-1, are expressed in the epithelial and smooth muscle cells. In addition to the G(q/11)-mediated activation of the phospholipase C beta pathway, epithelial PAR activation causes prompt and/or delayed prostanoid formation, leading to airway smooth muscle relaxation and/or modulation of an inflammatory process. PAR-2 present in the epithelium and smooth muscle is considered primarily pro-inflammatory in the respiratory system, although PAR-2 may also be anti-inflammatory under certain conditions. In the lung epithelial cells, PAR-2 can also be activated by exogenous proteinases including house dust mite allergens, in addition to various possible endogenous agonist proteinases. Clinical evidence also suggests possible involvement of PARs, particularly PAR-2, in respiratory diseases. PARs thus appear to play critical roles in the respiratory systems, and the agonists/antagonists for PARs may serve as the novel therapeutic strategy for treatment of certain respiratory diseases including asthma.
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Affiliation(s)
- Atsufumi Kawabata
- Division of Physiology and Pathophysiology, School of Pharmaceutical Sciences, Kinki University, Higashi-Osaka, Japan.
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