1
|
Oliveira KA, Torquato RJS, Lustosa DCGG, Ribeiro T, Nascimento BWL, de Oliveira LCG, Juliano MA, Paschoalin T, Lemos VS, Araujo RN, Pereira MH, Tanaka AS. Proteolytic activity of Triatoma infestans saliva associated with PAR-2 activation and vasodilation. J Venom Anim Toxins Incl Trop Dis 2021; 27:e20200098. [PMID: 33747067 PMCID: PMC7939238 DOI: 10.1590/1678-9199-jvatitd-2020-0098] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Background Triatoma infestans (Hemiptera: Reduviidae) is a
hematophagous insect and the main vector of Trypanosoma
cruzi (Kinetoplastida: Trypanosomatidae). In the present study,
the authors investigated whether a serine protease activity from the saliva
of T. infestans has a role in vasomotor modulation, and in
the insect-blood feeding by cleaving and activating protease-activated
receptors (PARs). Methods T. infestans saliva was chromatographed as previously
reported for purification of triapsin, a serine protease. The cleavage
activity of triapsin on PAR peptides was investigated based on FRET
technology. Mass spectrometry was used to analyze the sites of PAR-2 peptide
cleaved by triapsin. NO measurements were performed using the DAN assay
(2,3-diaminonapthalene). The vasorelaxant activity of triapsin was measured
in vessels with or without functional endothelium pre-contracted with
phenylephrine (3 µM). Intravital microscopy was used to assess the effect of
triapsin on mouse skin microcirculation. Results Triapsin was able to induce hydrolysis of PAR peptides and showed a higher
preference for cleavage of the PAR-2 peptide. Analysis by mass spectrometry
confirmed a single cleavage site, which corresponds to the activation site
of the PAR-2 receptor. Triapsin induced dose-dependent NO release in
cultured human umbilical vein endothelial cells (HUVECs), reaching a maximum
effect at 17.58 nM. Triapsin purified by gel-filtration chromatography
(10-16 to 10-9 M) was applied cumulatively to
mouse mesenteric artery rings and showed a potent endothelium-dependent
vasodilator effect (EC30 = 10-12 M). Nitric oxide
seems to be partially responsible for this vasodilator effect because L-NAME
(L-NG-nitroarginine methyl ester 300 µM), a nitric oxide synthetase
inhibitor, did not abrogate the vasodilation activated by triapsin.
Anti-PAR-2 antibody completely inhibited vasodilation observed in the
presence of triapsin activity. Triapsin activity also induced an increase in
the mouse ear venular diameter. Conclusion Data from this study suggest a plausible association between triapsin
activity mediated PAR-2 activation and vasodilation caused by T.
infestans saliva.
Collapse
Affiliation(s)
- Karla A Oliveira
- Department of Biochemistry and Pharmacology, Federal University of Piauí, Teresina, PI, Brazil
| | - Ricardo J S Torquato
- Department of Biochemistry, Federal University of São Paulo (Unifesp), São Paulo, SP, Brazil
| | - Daniela C G Garcia Lustosa
- Department of Pharmacology, Institute of Biomedical Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Tales Ribeiro
- Department of Parasitology, Institute of Biomedical Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Bruno W L Nascimento
- Department of Parasitology, Institute of Biomedical Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Lilian C G de Oliveira
- Department of Biophysics, National Institute of Pharmacology and Molecular Biology (INFAR), Federal University of São Paulo (Unifesp), São Paulo, SP, Brazil
| | - Maria A Juliano
- Department of Biophysics, National Institute of Pharmacology and Molecular Biology (INFAR), Federal University of São Paulo (Unifesp), São Paulo, SP, Brazil
| | - Thaysa Paschoalin
- Department of Biophysics, National Institute of Pharmacology and Molecular Biology (INFAR), Federal University of São Paulo (Unifesp), São Paulo, SP, Brazil
| | - Virginia S Lemos
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Ricardo N Araujo
- Department of Parasitology, Institute of Biomedical Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil.,National Institute of Science and Technology in Molecular Entomology (INCT-EM), Rio de Janeiro, RJ, Brazil
| | - Marcos H Pereira
- Department of Parasitology, Institute of Biomedical Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil.,National Institute of Science and Technology in Molecular Entomology (INCT-EM), Rio de Janeiro, RJ, Brazil
| | - Aparecida S Tanaka
- Department of Biochemistry, Federal University of São Paulo (Unifesp), São Paulo, SP, Brazil.,National Institute of Science and Technology in Molecular Entomology (INCT-EM), Rio de Janeiro, RJ, Brazil
| |
Collapse
|
2
|
SUN T, LIU R, CAO YX. Vasorelaxant and antihypertensive effects of formononetin through endothelium-dependent and -independent mechanisms. Acta Pharmacol Sin 2011; 32:1009-18. [PMID: 21818108 DOI: 10.1038/aps.2011.51] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
AIM To investigate the mechanisms underlying the vasorelaxant effect of formononetin, an O-methylated isoflavone, in isolated arteries, and its antihypertensive activity in vivo. METHODS Arterial rings of superior mesenteric arteries, renal arteries, cerebral basilar arteries, coronary arteries and abdominal aortas were prepared from SD rats. Isometric tension of the arterial rings was recorded using a myograph system. Arterial pressure was measured using tail-cuff method in spontaneously hypertensive rats. RESULTS Formononetin (1-300 μmol/L) elicited relaxation in arteries of the five regions that were pre-contracted by KCl (60 mmol/L), U46619 (1 μmol/L) or phenylephrine (10 μmol/L). The formononetin-induced relaxation was reduced by removal of endothelium or by pretreatment with L-NAME (100 μmol/L). Under conditions of endothelium denudation, formononetin (10, 30, and 100 μmol/L) inhibited the contraction induced by KCl and that induced by CaCl(2) in Ca(2+)-free depolarized medium. In the absence of extracellular Ca(2+), formononetin (10, 30, and 100 μmol/L) depressed the constriction caused by phenylephrine (10 μmol/L), but did not inhibit the tonic contraction in response to the addition of CaCl(2) (2 mmol/L). The contraction caused by caffeine (30 mmol/L) was not inhibited by formononetin (100 μmol/L). Formononetin (10 and 100 μmol/L) reduced the change rate of Ca(2+)-fluorescence intensity in response to KCl (50 mmol/L). In spontaneously hypertensive rats, formononetin (5, 10, and 20 mg/kg) slowly lowered the systolic, diastolic and mean arterial pressure. CONCLUSION Formononetin causes vasodilatation via two pathways: (1) endothelium-independent pathway, probably due to inhibition of voltage-dependent Ca(2+) channels and intracellular Ca(2+) release; and (2) endothelium-dependent pathway by releasing NO. Both the pathways may contribute to its antihypertensive effect.
Collapse
|
3
|
Abstract
Despite major advances in antiplatelet therapies, recurrent cardiovascular events remain high after acute coronary syndrome. Furthermore, incremental benefits achieved in the reduction of atherothrombotic events have almost always been at the expense of hemorrhagic side effects. Thrombin is the most potent platelet activating factor known and it makes important interactions with the endothelium and vascular smooth muscle with proinflammatory, proatherogenic effects. Distinct from its activity within the coagulation cascade, thrombin mediates these effects via protease-activated receptor type 1 (PAR-1) in man. This review discusses the role of PAR-1 in the vasculature and the development of novel PAR-1 antagonists. These drugs may provide important antiatherothrombotic effects without attendant bleeding complications and could represent a major breakthrough for the treatment of cardiovascular diseases.
Collapse
Affiliation(s)
- Ninian N Lang
- Centre for Cardiovascular Science, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, UK
| | | | | |
Collapse
|
4
|
Smeda JS, McGuire JJ, Daneshtalab N. Protease-activated receptor 2 and bradykinin-mediated vasodilation in the cerebral arteries of stroke-prone rats. Peptides 2010; 31:227-37. [PMID: 19954757 DOI: 10.1016/j.peptides.2009.11.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 11/20/2009] [Accepted: 11/23/2009] [Indexed: 10/20/2022]
Abstract
Protease-activated receptor 2 (PAR(2)) expression is up-regulated during vascular injury associated with edema. PAR(2) and bradykinin subtype 2 receptor (B(2)) expression and function were assessed in relation to hypertensive encephalopathy (HE) and cerebral hemorrhage (CH) in middle cerebral arteries (MCA) of Kyoto Wistar stroke-prone spontaneously hypertensive rats (SHRsp). Before stroke, bradykinin and PAR(2) activation by 2-furoyl-leucine-isoleucine-glycine-arginine-leucine-ornithine-amide (2Fly) produced endothelium-dependent vasodilation that was inhibited by K(+) depolarization, carbenoxolone, and the blockade of intermediate (IK(Ca)) plus small (SK(Ca)) and (in the case of bradykinin) smooth muscle (SM) large conductance (BK(Ca)) calcium-activated K(+) channels. Responses were not altered by N omega-nitro-L-arginine methyl ester, indomethacin, 17-octadecynoic acid or Ba(2+)+ouabain. We concluded that vasodilation to 2Fly or bradykinin was not mediated by NO, cyclooxygenases, arachidonic acid-metabolizing cytochrome P450s or SM K(ir) channels+Na(+)/K(+) ATPase activation. Vasodilation likely involved the spread of endothelial hyperpolarization (generated by IK(Ca)+SK(Ca)) through myoendothelial junctions and in some cases SM BK(Ca) activation. SHRsp with HE or CH had MCA that could not constrict to pressure and did not vasodilate to bradykinin. Their responses to 2Fly remained unaltered. The patterns and densities of PAR(2) and B(2) immunoreactivity in frozen MCA sections were not altered with stroke. MCA function remained normal in SHRsp subjected to dietary manipulations that prevented stroke without altering hypertension. Despite the presence of vascular injury, edema, inflammation and the loss of endothelium-dependent bradykinin vasodilation we found no evidence that PAR(2) expression or vascular function was altered in MCA after stroke.
Collapse
MESH Headings
- Animals
- Blood Pressure/physiology
- Bradykinin/pharmacology
- Calcium Channel Blockers/pharmacology
- Cyclooxygenase Inhibitors/pharmacology
- Cytochrome P-450 Enzyme Inhibitors
- Diet
- Disease Models, Animal
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Gap Junctions/drug effects
- Hypertensive Encephalopathy/pathology
- Hypertensive Encephalopathy/physiopathology
- Intermediate-Conductance Calcium-Activated Potassium Channels/antagonists & inhibitors
- Intracranial Hemorrhage, Hypertensive/pathology
- Intracranial Hemorrhage, Hypertensive/physiopathology
- Large-Conductance Calcium-Activated Potassium Channels/antagonists & inhibitors
- Male
- Membrane Potentials/drug effects
- Middle Cerebral Artery/drug effects
- Middle Cerebral Artery/metabolism
- Middle Cerebral Artery/physiopathology
- Nifedipine/pharmacology
- Nitric Oxide/antagonists & inhibitors
- Nitric Oxide/metabolism
- Rats
- Rats, Inbred SHR
- Receptor, Bradykinin B2/metabolism
- Receptor, PAR-2/agonists
- Receptor, PAR-2/metabolism
- Receptors, KIR/antagonists & inhibitors
- Small-Conductance Calcium-Activated Potassium Channels/antagonists & inhibitors
- Sodium Chloride, Dietary/pharmacology
- Sodium-Potassium-Exchanging ATPase/antagonists & inhibitors
- Stroke/pathology
- Stroke/physiopathology
- Vasoconstriction/physiology
- Vasodilation/drug effects
- Vasodilation/physiology
Collapse
Affiliation(s)
- John S Smeda
- Division of BioMedical Sciences, Memorial University, St. John's, Newfoundland, Canada.
| | | | | |
Collapse
|
5
|
Matsumoto T, Ishida K, Taguchi K, Kobayashi T, Kamata K. Mechanisms underlying enhanced vasorelaxant response to protease-activated receptor 2-activating peptide in type 2 diabetic Goto-Kakizaki rat mesenteric artery. Peptides 2009; 30:1729-34. [PMID: 19540892 DOI: 10.1016/j.peptides.2009.06.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Revised: 06/10/2009] [Accepted: 06/11/2009] [Indexed: 01/06/2023]
Abstract
Protease-activated receptor 2 (PAR2) is a G-protein-coupled receptor that is proteolytically activated by certain endogenous proteases, such as trypsin, tryptase, and factor Xa. PAR2 can also be activated by synthetic peptides if their sequence mimics the tethered ligand exposed after receptor cleavage. Although it is known that PAR2 modulates vascular reactivity, it is unclear whether at the chronic stage of type 2 diabetes there are alterations in PAR2-mediated vascular responses. We investigated this issue by exposing mesenteric artery rings to PAR2-activating peptide (PAR2-AP; SLIGRL-NH(2)), the arteries used being obtained from later-stage (32-40-week-old) type 2 diabetic Goto-Kakizaki (GK) rats. The PAR2-AP-induced relaxation was enhanced in GK rats (vs. age-matched Wistar rats), whereas the ACh-induced relaxation was weaker in GK than in Wistar rats. In both groups, the PAR2-AP-induced relaxation was largely blocked by endothelial denudation or by N(G)-nitro-L-arginine [nitric oxide (NO) synthase inhibitor] treatment, but it was unaffected by indomethacin (cyclooxygenase inhibitor) treatment. Both the NO production induced by PAR2-AP and the PAR2 protein expression were significantly increased in mesenteric arteries from GK rats (vs. Wistar rats). These data are the first to indicate that the PAR2-AP-induced endothelium-dependent relaxation is enhanced in mesenteric arteries isolated from type 2 diabetic GK rats at the chronic stage, and they further suggest that the enhancement may be due to an increased expression of PAR2 receptors in this artery.
Collapse
Affiliation(s)
- Takayuki Matsumoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo, Japan
| | | | | | | | | |
Collapse
|
6
|
Kawabata A, Matsunami M, Sekiguchi F. Gastrointestinal roles for proteinase-activated receptors in health and disease. Br J Pharmacol 2007; 153 Suppl 1:S230-40. [PMID: 17994114 DOI: 10.1038/sj.bjp.0707491] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
It has been almost a decade since the molecular cloning of all four members of the proteinase-activated receptor (PAR) family was completed. This unique family of G protein-coupled receptors (GPCRs) mediates specific cellular actions of various endogenous proteinases including thrombin, trypsin, tryptase, etc. and also certain exogenous enzymes. Increasing evidence has been clarifying the emerging roles played by PARs in health and disease. PARs, particularly PAR1 and PAR2, are distributed throughout the gastrointestinal (GI) tract, modulating various GI functions. One of the most important GI functions of PARs is regulation of exocrine secretion in the salivary glands, pancreas and GI mucosal epithelium. PARs also modulate motility of GI smooth muscle, involving multiple mechanisms. PAR2 appears to play dual roles in pancreatitis and related pain, being pro-inflammatory/pro-nociceptive and anti-inflammatory/anti-nociceptive. Similarly, dual roles for PAR1 and PAR2 have been demonstrated in mucosal inflammation/damage throughout the GI tract. There is also fundamental and clinical evidence for involvement of PAR2 in colonic pain. PARs are thus considered key molecules in regulation of GI functions and targets for development of drugs for treatment of various GI diseases.
Collapse
Affiliation(s)
- A Kawabata
- Division of Pharmacology and Pathophysiology, Kinki University School of Pharmacy, Higashi-Osaka, Japan.
| | | | | |
Collapse
|
7
|
Gloro R, Ducrotte P, Reimund JM. Protease-activated receptors: potential therapeutic targets in irritable bowel syndrome? Expert Opin Ther Targets 2007; 9:1079-95. [PMID: 16185159 DOI: 10.1517/14728222.9.5.1079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Protease-activated receptors (PARs) are a family of four G-protein-coupled receptors (PAR-1 to PAR-4) activated by the proteolytic cleavage of their N-terminal extracellular domain. This activation first involves the recognition of the extracellular domain by proteases, such as thrombin, but also trypsin or tryptase which are particularly abundant in the gastrointestinal tract, both under physiological circumstances and in several digestive diseases. Activation of PARs, particularly of PAR-1 and -2, modulates intestinal functions, such as gastrointestinal motility, visceral nociception, mucosal inflammatory response, and epithelial functions (intestinal secretion and permeability). As these physiological properties have been shown to be altered in various extents and combinations in different clinical presentations of irritable bowel syndrome, PARs appear as putative targets for future therapeutic intervention in these patients.
Collapse
Affiliation(s)
- Romain Gloro
- Centre Hospitalier Universitaire de Caen, Service d'Hépato-Gastro-Entérologie et Nutrition, Avenue de la Côte de Nacre, 14033 Caen Cedex, France
| | | | | |
Collapse
|
8
|
Nishiyama T, Nakamura T, Obara K, Inoue H, Mishima K, Matsumoto N, Matsui M, Manabe T, Mikoshiba K, Saito I. Up-Regulated PAR-2-Mediated Salivary Secretion in Mice Deficient in Muscarinic Acetylcholine Receptor Subtypes. J Pharmacol Exp Ther 2006; 320:516-24. [PMID: 17077315 DOI: 10.1124/jpet.106.113092] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Protease-activated receptor-2 (PAR-2) is expressed in the salivary glands and is expected to be a new target for the treatment of exocrine dysfunctions, such as dry mouth; however, the salivary secretory mechanism mediated by PAR-2 remains to be elucidated. Therefore, mechanism of the PAR-2-mediated salivary secretion was investigated in this study. We found that a PAR-2 agonist peptide, SLIGRL-OH, induced salivary flow in vivo and dose-dependent increase in [Ca(2+)](i) submandibular gland (SMG) acinar cells in wild-type (WT) mice and mice lacking M(3) or both M(1) and M(3) muscarinic acetylcholine receptors (mAChRs), whereas secretions in PAR-2 knockout (PAR-2KO) mice were completely abolished. The saliva composition secreted by SLIGRL-OH was similar to that secreted by mAChR stimulation. Ca(2+) imaging in WT acinar cells and beta-galactosidase staining in PAR-2KO mice, in which the beta-galactosidase gene (LacZ) was incorporated into the disrupted gene, revealed a nonubiquitous, sporadic distribution of PAR-2 in the SMG. Furthermore, compared with the secretion in WT mice, PAR-2-mediated salivary secretion and Ca(2+) response were enhanced in mice lacking M(3) or both M(1) and M(3) mAChRs, in which mAChR-stimulated secretion and Ca(2+) response in acinar cells were severely impaired. Although the mechanism underlying the enhanced PAR-2-mediated salivary secretion in M(3)-deficient mice is not clear, the result suggests the presence of some compensatory mechanism involving PAR-2 in the salivary glands deficient in cholinergic activation. These results indicate that PAR-2 present in the salivary glands mediates Ca(2+)-dependent fluid secretion, demonstrating potential usefulness of PAR-2 as a target for dry mouth treatment.
Collapse
Affiliation(s)
- Tatsuaki Nishiyama
- Department of Pathology, Tsurumi University School of Dental Medicine, Tsurumi-ku, Yokohama, 230-8501, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Gudmundsdóttir IJ, Megson IL, Kell JS, Ludlam CA, Fox KAA, Webb DJ, Newby DE. Direct Vascular Effects of Protease-Activated Receptor Type 1 Agonism In Vivo in Humans. Circulation 2006; 114:1625-32. [PMID: 17015787 DOI: 10.1161/circulationaha.106.638478] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
Protease-activated receptor type 1 (PAR-1) has been proposed as the principal thrombin receptor in humans, although its actions in vivo have not been defined. The aim of the present study was to determine the direct vascular actions of PAR-1 agonism in humans.
Methods and Results—
Dorsal hand vein diameter was measured by the Aellig technique in 14 healthy volunteers during local intravenous SFLLRN (PAR-1 agonist; 0.05 to 15 nmol/min) and SLIGKV (PAR-2 agonist; 1.6 to 160 nmol/min) infusions. The venous effects of SFLLRN were further assessed in the presence or absence of norepinephrine or the glycoprotein IIb/IIIa antagonist tirofiban. Forearm blood flow was measured by venous occlusion plethysmography in 16 volunteers during infusion of SFLLRN (1 to 50 nmol/min), SLIGKV (160 to 800 nmol/min), and the endothelium-dependent vasodilator bradykinin (100 to 1000 pmol/min). Platelet-monocyte binding (a sensitive measure of platelet activation) and plasma tissue plasminogen activator (tPA), plasminogen-activator inhibitor 1, and von Willebrand factor concentrations were measured at intervals throughout the study. SFLLRN caused dose-dependent venoconstriction (
P
<0.001) that was unaffected by norepinephrine or tirofiban co-infusion. In forearm resistance vessels, SFLLRN increased forearm blood flow (
P
<0.001), tPA release (
P
<0.001), and platelet-monocyte binding (
P
<0.0001) without affecting plasma plasminogen-activator inhibitor 1 or von Willebrand factor concentrations. SLIGKV caused venous (
P
<0.001) and arterial (
P
<0.01) dilatation without tPA release.
Conclusions—
We have demonstrated that PAR-1 agonism causes platelet activation, venous constriction, arterial dilatation, and tPA release in vivo in humans. These unique and contrasting effects provide important insights into the physiological and pathophysiological role of thrombin in the human venous and arterial circulations.
Collapse
Affiliation(s)
- Ingibjörg J Gudmundsdóttir
- Centre for Cardiovascular Science, University of Edinburgh, Royal Infirmary, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
| | | | | | | | | | | | | |
Collapse
|
10
|
Nishikawa H. [Roles of protease-activated receptor-2 (PAR-2), a G protein-coupled receptor, in modulation of exocrine gland functions]. YAKUGAKU ZASSHI 2006; 126:481-8. [PMID: 16819269 DOI: 10.1248/yakushi.126.481] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Protease-activated receptor-2 (PAR-2), a G protein-coupled receptor, is activated by proteolytic unmasking of the N-terminal extracellular tethered ligand that presumably binds to the extracellular loop 2 of the receptor itself. PAR-2 is widely distributed in the mammalian body and plays various roles in biological events in the cardiovascular, respiratory, alimentary, and central neurons systems. PAR-2-activating peptides administered systemically to mice and rats trigger prompt salivation in vivo. In an in vitro study, PAR-2 agonists including the endogenous PAR-2 activator trypsin induce secretion of amylase and mucin from isolated rat parotid glands and sublingual glands, respectively. PAR-2-activating peptides administered systemically also modulate pancreatic exocrine secretion in vivo as well as in vitro. In the gastric mucosa, PAR-2 stimulation enhances secretion of mucus and pepsinogen and suppresses acid secretion. Tear secretion can also be caused by PAR-2-related peptides in PAR-2-dependent and -independent manners. PAR-2 thus plays a general or key role in the regulation of exocrine secretion. This review focuses on the physiologic and/or pathophysiologic roles of PAR-2 in glandular exocrine secretion. The possibility of PAR-2 as a target for drug development is also discussed.
Collapse
Affiliation(s)
- Hiroyuki Nishikawa
- Research and Development Center, Fuso Pharmaceutical Industries, Ltd., Morinomiya, Osaka, Japan.
| |
Collapse
|
11
|
Sekiguchi F, Saito S, Takaoka K, Hayashi H, Nagataki M, Nagasawa K, Nishikawa H, Matsui H, Kawabata A. Mechanisms for prostaglandin E2 formation caused by proteinase-activated receptor-1 activation in rat gastric mucosal epithelial cells. Biochem Pharmacol 2006; 73:103-14. [PMID: 17069767 DOI: 10.1016/j.bcp.2006.09.016] [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: 07/06/2006] [Revised: 09/14/2006] [Accepted: 09/15/2006] [Indexed: 12/24/2022]
Abstract
Proteinase-activated receptor-1 (PAR1), a thrombin receptor, plays a protective role in gastric mucosa via prostanoid formation. Thus, we studied effects of PAR1 stimulation on prostaglandin E(2) (PGE(2)) formation in rat normal gastric mucosal epithelial RGM1 cells and analyzed the underlying signal transduction mechanisms. The PAR1-activating peptide (PAR1-AP) and thrombin increased PGE(2) release from RGM1 cells for 18h, an effect being suppressed by inhibitors of COX-1, COX-2, MEK, p38 MAP kinase (p38 MAPK), protein kinase C (PKC), Src and EGF receptor-tyrosine kinase (EGFR-TK), but not JNK and matrix metalloproteinase (MMP)/a disintegrin and metalloproteinases (ADAMs). PAR1-AP caused persistent (6h or more) and transient (5min) phosphorylation of ERK and p38 MAPK, respectively, followed by delayed reinforcement at 18h. PAR1-AP up-regulated COX-2 in a manner dependent on MEK and EGFR-TK, but not p38 MAPK. The PAR1-mediated persistent ERK phosphorylation was reduced by inhibitors of Src and EGFR-TK. PAR1-AP actually phosphorylated EGF receptors and up-regulated mRNA for heparin-binding-EGF (HB-EGF), the latter effect being blocked by inhibitors of Src, EGFR-TK and MEK. Heparin, an inhibitor for HB-EGF, suppressed PAR1-mediated PGE(2) formation and persistent ERK phosphorylation. These results suggest that PAR1 up-regulates COX-2 via persistent activation of MEK/ERK that is dependent on EGFR-TK activation following induction of HB-EGF, leading to PGE(2) formation. In addition, our data also indicate involvement of COX-1, PKC and p38 MAPK in PAR1-triggered PGE(2) formation. PAR1, thus stimulates complex multiple signaling pathways responsible for PGE(2) formation in RGM1 cells.
Collapse
Affiliation(s)
- Fumiko Sekiguchi
- Division of Physiology and Pathophysiology, School of Pharmacy, Kinki University, 3-4-1 Kowakae, Higashi-Osaka 577-8502, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
12
|
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]
|
13
|
Bucci M, Roviezzo F, Cirino G. Protease-activated receptor-2 (PAR2) in cardiovascular system. Vascul Pharmacol 2005; 43:247-53. [PMID: 16183333 DOI: 10.1016/j.vph.2005.07.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2002] [Accepted: 07/29/2005] [Indexed: 12/22/2022]
Abstract
Vascular system is constituted by a complex and articulate network, e.g. arteries, arterioles, venules and veins, that requires a high degree of coordination between different elemental cell types. Proteinase-activated receptors (PARs) constitute a recent described family of 7-transmembrane G protein-coupled receptors that are activated by proteolysis. In recent years several evidence have been accumulated for an involvement of this receptor in the response to endothelial injury in vitro and in vivo experimental settings suggesting a role for PAR2 in the pathophysiology of cardiovascular system. This review will deal with the role of PAR2 receptor in the cardiovascular system analyzing both in vivo and in vitro published data. In particular this review will deal with the role of this receptor in vascular reactivity, ischemia/reperfusion injury, coronary atherosclerotic lesions and angiogenesis.
Collapse
Affiliation(s)
- Mariarosaria Bucci
- Department of Experimental Pharmacology, Faculty of Pharmacy, University of Naples Federico II via Domenico Montesano 49, 80131 Naples, Italy.
| | | | | |
Collapse
|