Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Proteinase-activated receptor 2 (PAR2) is cleaved and activated by trypsin or mast cell tryptase, and may play an important role in inflammation. We have investigated the potential of PAR2 agonists to modulate TNF-alpha secretion from human astrocytoma cell line CCF-STTG1. We found that CCF-STTG1 expresses PAR2 by RT-PCR and Western blot analysis. Agonists such as trypsin, the peptide SLIGKV-NH(2) (corresponding to the PAR2 tethered ligand), or mast cell tryptase directly signal to CCF-STTG1 to stimulate secretion of TNF-alpha but do not stimulate in the presence of soybean trypsin inhibitor (SBTI) or VKGILS-NH(2) (reverse peptide). The secretion of TNF-alpha by trypsin was significantly blocked by pretreatment with either 50 microM PD98059 or 1 microM SB203580. Furthermore, trypsin stimulated the activation of extracellular signal-regulated kinase (ERK) and p38 MAP kinase homologue in CCF-STTG1 without any detectable activation of c-Jun N-terminal kinase (JNK). These results show that trypsin may induce TNF-alpha secretion following activation of ERK and p38 via PAR2 in CCF-STTG1.
...
PMID:Agonists of proteinase-activated receptor 2 induce TNF-alpha secretion from astrocytoma cells. 1241 69

The proteinase-activated receptor-2 (PAR-2) is a G protein-coupled receptor that is cleaved and activated by trypsin. To clarify the presence of PAR-2 in human pancreatic cancer, the expression of PAR-2 was analyzed by RT-PCR, immunoblotting and immunocytochemistry using 5 human pancreatic cancer cell lines. And to evaluate the biological significance, immunohistochemical expression of PAR-2 in malignant and non-malignant human pancreatic tissues was examined using paraffin-embedded sections. The presence of PAR-2 was confirmed in all 5 pancreatic cancer cell lines and all 21 paraffin-embedded specimens from human pancreatic cancer examined. The expression of PAR-2 was found to be higher in the tissues with infiltrative growth pattern than those with expansive growth pattern. Moreover, significantly higher expression of PAR-2 was observed in the tissues which were accompanied by severe fibrosis. Even in the same specimen, the intensity of immunoreactivity tended to be stronger in the part with severe fibrosis than that with mild fibrosis. Similarly, the higher expression of PAR-2 was observed in chronic pancreatitis with severe fibrosis than with mild fibrosis. Taken together, these results suggest that the activation of PAR-2 is involved in cancer invasion and the induction of fibrosis in human pancreatic cancer.
...
PMID:Expression of proteinase-activated receptor-2 in human pancreatic cancer: a possible relation to cancer invasion and induction of fibrosis. 1252 25

Mast cells that are in close proximity to autonomic and enteric nerves release several mediators that cause neuronal hyperexcitability. This study examined whether mast cell tryptase evokes acute and long-term hyperexcitability in submucosal neurons from the guinea-pig ileum by activating proteinase-activated receptor 2 (PAR2) on these neurons. We detected the expression of PAR2 in the submucosal plexus using RT-PCR. Most submucosal neurons displayed PAR2 immunoreactivity, including those colocalizing VIP. Brief (minutes) application of selective PAR2 agonists, including trypsin, the activating peptide SL-NH2 and mast cell tryptase, evoked depolarizations of the submucosal neurons, as measured with intracellular recording techniques. The membrane potential returned to resting values following washout of agonists, but most neurons were hyperexcitable for the duration of recordings (> 30 min-hours) and exhibited an increased input resistance and amplitude of fast EPSPs. Trypsin, in the presence of soybean trypsin inhibitor, and the reverse sequence of the activating peptide (LR-NH2) had no effect on neuronal membrane potential or long-term excitability. Degranulation of mast cells in the presence of antagonists of established excitatory mast cell mediators (histamine, 5-HT, prostaglandins) also caused depolarization, and following washout of antigen, long-term excitation was observed. Mast cell degranulation resulted in the release of proteases, which desensitized neurons to other agonists of PAR2. Our results suggest that proteases from degranulated mast cells cleave PAR2 on submucosal neurons to cause acute and long-term hyperexcitability. This signalling pathway between immune cells and neurons is a previously unrecognized mechanism that could contribute to chronic alterations in visceral function.
...
PMID:Mast cell tryptase and proteinase-activated receptor 2 induce hyperexcitability of guinea-pig submucosal neurons. 1256 62

In intact cells, trypsin activates proteinase-activated receptor-2 (PAR(2)) by hydrolysis at residues R(36)/S(37) (amino acids are abbreviated by their one-letter code), revealing an active tethered ligand sequence. We sought to determine whether in intact cells, the tryptic cleavage/activation of PAR(2) might also be accompanied by hydrolysis at other potential N-terminal cleavage sites, like residues K(34), R(41), K(51), and K(72), as implied by the tryptic cleavage in vitro at these residues of Escherichia coli-expressed human N-terminal PAR(2)R(31)-P(79). To this end, four PAR(2) mutants with altered tryptic cleavage sites were prepared (PAR(2)R(36)A, PAR(2)S(37)P, PAR(2)R(41)A, and PAR(2)R(36)AR(41)A), expressed in Kirsten virus-transformed rat kidney cells and were evaluated together with the wild-type PAR(2)-expressing cells for 1) activation (Ca(2+) signaling) by trypsin and the receptor-activating peptide SLIGRL-NH(2) (SL-NH(2)) and 2) the tryptic release of two antigenic receptor determinants, one N-terminal to the R(36)/S(37) cleavage/activation site detected by SLAW-A antibody and the second (detected by antibody, B5), N-terminal to residues K(51), K(72). None of the mutants resistant to cleavage at R(36) were activated by trypsin, yet all retained reactivity to B5 and all were activated by SL-NH(2). In contrast, trypsin activated both wild-type and PAR(2)R(41)A, leading to a disappearance of SLAW-A but not B5 reactivity. We conclude that, as opposed to the E. coli-expressed PAR(2) N-terminal polypeptide, PAR(2) expressed in intact cells displays selective tryptic cleavage at the R(36)/S(37) activation site, without cleaving downstream. Thus, in intact cells, trypsin activation does not concurrently "disarm" rat PAR(2), but leaves the "tethered ligand" persistently attached to the body of the receptor.
...
PMID:Selective tryptic cleavage at the tethered ligand site of the amino terminal domain of proteinase-activated receptor-2 in intact cells. 1260 89

Radiation damage results in blood-brain barrier damage followed by blood plasma transfer into the neuropil. The transferred liquid contains high amounts of biologically active substances/proteinases including factor Xa and a free pool of serum trypsin, which is not bound to antiproteases (alpha1 AT, alpha2-macroglobulin). The aim of this study was to follow up expression of proteinase-activated receptor-2 (PAR-2) in the brains of Wistar rats after single exposure to radiation at 26 Gy (60Co, 23 min, 15 sec). After irradiation, the animals were sacrificed on days 10, 20, 30 and 40. Control rat brains served as negative control. Coronal sections of caudal diencephalons were investigated using histology and immunohistochemistry. Polyclonal goat specified antibody against the NH-end of murine and rat PAR-2. Significant PAR-2 membrane positivity of scattered swollen neurons in deeper cortical layers was found in irradiated animals compared with controls. Although this membrane positivity was noticed in all irradiated animals, the most prominent occurred on day 30. Diffuse cytoplasmic positivity was also demonstrated on shrunken neurons in the cortex and hippocampus. Increased cytoplasmic and polarized membrane positivity was also noticed on the neurons of hypothalamic nuclei The causal relationship between blood-brain barrier damage, PAR-2 activation and neurodegeneration has not yet been verified. However, the present findings indicate that PAR-2 mediates a certain cellular response. It remains to be demonstrated whether this is a response to higher concentrations of factor Xa, a free pool of trypsin or other unknown possible proteinases in brain tissue; whether changes in PAR-2 expression are consequences of direct radiation damage to neuronal cells; whether this reaction is protective; and whether primary PAR-2 activation results in neuronal damage.
...
PMID:Proteinase-activated receptor-2 expression on cerebral neurones after radiation damage: immunohistochemical observation in Wistar rats. 1263 60

We report here a direct modulation by mast cell tryptase of endothelial barrier function through activation of proteinase-activated receptor-2 (PAR-2). In cultured bovine aortic endothelial cells (BAECs), tryptase, trypsin and PAR-2 activating peptide impaired the barrier function as determined by the permeability of protein-conjugated Evans blue. The tryptase-induced barrier dysfunction was completely blocked by U73122, and partially reversed by xestospongin C, calphostin C or Y27632. The intracellular Ca(2+) was elevated by tryptase. It was notable that ioxaglate, a contrast material that degranulates mast cells, markedly increased the permeability when applied to BAECs in combination with mast cells, an action that was blocked by nafamostat, a potent tryptase inhibitor. Immunofluorescence analysis showed that actin stress fibre formation and disruption of VE-cadherin were observed after exposure to tryptase or ioxaglate in combination with mast cells. Therefore, it is suggested that mast cell tryptase impairs endothelial barrier function through activation of endothelial PAR-2 in a manner dependent on the phospholipase C activity.
...
PMID:Involvement of proteinase-activated receptor-2 in mast cell tryptase-induced barrier dysfunction in bovine aortic endothelial cells. 1278 70

We examined whether neuronal proteinase-activated receptor-2 (PAR-2) may be involved in pruritus of human skin. The endogenous PAR-2 agonist tryptase was increased up to fourfold in atopic dermatitis (AD) patients. PAR-2 was markedly enhanced on primary afferent nerve fibers in skin biopsies of AD patients. Intracutaneous injection of endogenous PAR-2 agonists provoked enhanced and prolonged itch when applied intralesionally. Moreover, itch upon mast cell degranulation was abolished by local antihistamines in controls but prevailed in AD patients. Thus, we identified enhanced PAR-2 signaling as a new link between inflammatory and sensory phenomena in AD patients. PAR-2 therefore represents a promising therapeutic target for the treatment of cutaneous neurogenic inflammation and pruritus.
...
PMID:Proteinase-activated receptor-2 mediates itch: a novel pathway for pruritus in human skin. 1286

The mast cell serine protease tryptase has been implicated as a critical mediator of airway hyperresponsiveness in vitro and in vivo. We have previously demonstrated that tryptase promotes hyperresponsiveness in isolated guinea pig bronchi. In this study, we have investigated the potential role of tryptase-mediated activation of proteinase-activated receptor-2 (PAR-2) in promoting airway hyperresponsiveness. Ex vivo exposure of guinea pig bronchi to the PAR-2 agonists H(2)N-Ser-Leu-Ile-Gly-Arg-Leu-CONH(2) (SLIGRL) and t-cinnamoyl-H(2)N-Leu-Ile-Gly-Arg-Leu-O-CONH(2) (t-c-LIGRLO) (0.1-10 microM) induced a concentration-dependent increase of contractile response to histamine. Treatment with 10 microM SLIGRL or t-c LIGRLO for 45 min increased subsequent responsiveness to histamine (0.3mM) by 54+/-3% and 69+/-5%, respectively (P<0.05 vs. control). In contrast, the PAR-1 agonist peptide H(2)N-Ser-Phe-Leu-Leu-Arg-Asn-CONH(2) (SFLLRN) did not promote significant changes in the airway. Effects of the peptides were observed following at least a 30-min preincubation with the tissue. Coincubation with indomethacin or removal of epithelial cells is required for PAR-2-mediated hyperreactivity. The inactive analogue H(2)N-Leu-Ser-Ile-Gly-Arg-Leu-CONH(2) (LISGRL; 10 microM) failed to promote hyperresponsiveness. Neuropeptide antagonists blocked the effect of the PAR-2 agonists. Selective antagonists of NK1 (L-703,606), NK2 (L-659,877), and CGRP (alphaCGRP 8-37) provided additive inhibition of PAR-2-mediated hyperreactivity. Pretreatment of bronchi with capsaicin (0.8 microM) also prevented the effects of SLIGRL. These results demonstrate the potential involvement of tryptase-mediated activation of PAR-2 in promoting airway hyperresponsiveness. These results further demonstrate that the PAR-2-mediated response involves a neurogenic mechanism involving neuropeptide release.
...
PMID:Proteinase-activated receptor-2 mediates hyperresponsiveness in isolated guinea pig bronchi. 1290 52

Proteinase-activated receptor 2 (Par2, F2rl1, also designated PAR-2 or PAR2) is prominently expressed in the intestine and has been suggested as a mediator of inflammatory, mitogenic and fibrogenic responses to injury. Mast cell proteinases and pancreatic trypsin, both of which have been shown to affect the intestinal radiation response, are the major biological activators of Par2. Conventional Sprague-Dawley rats, mast cell-deficient rats, and rats in which pancreatic exocrine secretion was blocked pharmacologically by octreotide underwent localized irradiation of a 4-cm loop of small bowel. Radiation injury was assessed 2 weeks after irradiation (early, inflammatory phase) and 26 weeks after irradiation (chronic, fibrotic phase). Par2 expression and activation were assessed by in situ hybridization and immunohistochemistry, using antibodies that distinguished between total (preactivated and activated) Par2 and preactivated Par2. Compared to unirradiated intestine, irradiated intestine exhibited increased Par2 expression, particularly in areas of myofibroblast proliferation and collagen accumulation, after both single-dose and fractionated irradiation. The majority of Par2 expressed in fibrotic areas was activated. Postirradiation Par2 overexpression was greatly attenuated in both mast cell-deficient and octreotide-treated rats. The severity of acute mucosal injury did not affect postirradiation Par2 expression. Mast cells and pancreatic proteinases may exert their fibro-proliferative effects partly through activation of Par2. Par2 may be a potential target for modulating the intestinal radiation response, particularly delayed intestinal wall fibrosis.
...
PMID:Up-regulation and activation of proteinase-activated receptor 2 in early and delayed radiation injury in the rat intestine: influence of biological activators of proteinase-activated receptor 2. 1456 30

C-terminal truncation mutants were made to investigate the role of the C-terminus in coupling proteinase-activated receptor-2 (PAR-2) to various signalling pathways. Membrane expression of the delta15, delta34, delta43, and delta34-43 mutants was similar; however, expression of deltatail was lost, as was agonist-mediated internalisation of deltatail, delta43, and delta34-43. Additionally, trypsin and SLIGKV-stimulated [3H]IP accumulation was abrogated in cells transiently expressing delta43 or delta34-43 truncations, but remained unaffected in cells expressing delta34 or delta15. PAR-2 agonist-stimulated intracellular Ca(2+) mobilisation and PYK-2 activity were also abolished by deltatail, delta43, and delta34-43 mutants. However, trypsin-stimulated stress-activated protein kinases (SAPKs) or extracellular signal-regulated kinase (ERK) activities were unaffected by the delta34-43 mutation, although activity was abrogated following delta43 or deltatail truncations, suggesting that Ca(2+) mobilisation, PYK-2, or receptor internalisation are not requied for activation of SAPKs or ERK. These studies identify a novel sequence within the PAR-2 C-terminus essential for InsP(3) generation and PYK-2 activity but not mitogen-activated protein kinase (MAPK) activation.
...
PMID:The role of the C-terminal tail in protease-activated receptor-2-mediated Ca2+ signalling, proline-rich tyrosine kinase-2 activation, and mitogen-activated protein kinase activity. 1460 72


<< Previous 1 2 3 4 5 6 7 8 9 Next >>

---