Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lysophosphatidylcholine (LPC) increases extracellularly during ischemia in vivo in both animals and man as judged by measurements from venous effluents, but more recent studies have shown little or no increase in buffer-perfused, isolated heart preparations. The appearance of LPC in blood and lymph in animals and in venous effluents in man in response to ischemia suggests a vascular site for the production of LPC. The present study was performed to assess whether thrombin could stimulate phospholipase A2 in endothelial cells and whether this would evoke an increase in and release of LPC. Endothelial cells were disassociated from canine aortas by incubating with 0.1% collagenase for 20 min. Cells were plated and allowed to grow to confluence. Measurement of LPC was performed using Bligh and Dyer extraction of lipids, high performance liquid chromatography separation, and quantification of LPC using a recently developed radiometric assay employing [3H]acetic anhydride. Incubation of endothelial cells with thrombin (0.05 unit/ml) resulted in a 2.5-fold increase in LPC to 2.3 +/- 0.1 nmol/mg of protein at 2 min (p < 0.01) and returned to control levels within 20 min. The increase in LPC induced by thrombin exhibited a concentration-dependent response with an ED50 = 0.04 unit/ml. A concentration-dependent increase in LPC was also elicited by stimulation with the peptide portion of the thrombin receptor's tethered ligand SFLLRNPNDKYEPF with an ED50 = 8 microM. The LPC produced was rapidly and completely released into the surrounding media. Hirudin completely blocked the thrombin-induced increase in LPC. Dansylarginine N-(3-ethyl-1,5-pentanediyl)amide (0.1 microM), which rapidly inactivates thrombin's proteolytic activity in situ without impairing binding, or phenyl-prolyl-arginyl-chloromethyl ketone (PPACK, 5 nM), which inactivates thrombin due to chemical alteration of the proteolytic site, each prevented the increase in LPC in response to thrombin. Stimulation of protein kinase C with phorbol 12-myristate-13-acetate (PMA, 1 microM) enhanced the response to thrombin. In contrast, staurosporine (100 nM), H7 (15 microM), or chronic treatment with PMA for 20 h to down-regulate protein kinase C completely prevented the increase in LPC in response to thrombin. Thus, thrombin stimulation of endothelial cells in vivo during ischemia may be a primary mechanism contributing to the marked increase in LPC extracellularly during ischemia.
 ...
PMID:Thrombin-induced release of lysophosphatidylcholine from endothelial cells. 839 49

Matrix metalloproteinases (MMPs) are responsible for the degradation of extracellular matrix components and are secreted by a variety of cells including human endothelial cells. Because alpha-thrombin is known to interact with matrix components and has been shown to activate latent MMP-2 in human umbilical vein endothelial cells, we investigated whether human alpha-thrombin could also regulate other MMPs secreted by the human saphenous vein or mammary artery endothelial cells (EC). After treatment of EC with increasing concentrations of thrombin for different periods of time, a significantly higher gelatinolytic activity of both MMP-1 and MMP-3 was observed in addition to MMP-2 activation. The effect of thrombin was time and dose-dependent, reaching a maximum at 24 hours. After treatment with 5 NIH U/ml thrombin for 24 hours, Western blotting revealed 9.5- and 4.4-fold increases over control values for MMP-3 and MMP-1, respectively. The synthetic thrombin receptor agonist peptide SFLLRNPNDKYEPF fully reproduced the action of thrombin, whereas chemical inactivation of the catalytic site of thrombin abolished its effect on MMP-1 and MMP-3. Thrombin and SFLLRNPNDKYEPF both induced MMP-3 mRNA synthesis but had no significant influence on constitutive MMP-1 mRNA levels. These results demonstrate that thrombin not only activates latent MMP-2 but also modulates MMP-1 and MMP-3 production in EC, this latter effect being mediated by the G-protein-coupled thrombin receptor. Hence, our present data provide evidence to support the suspected role of thrombin in tissue remodeling and angiogenesis.
 ...
PMID:Thrombin receptor-mediated increase of two matrix metalloproteinases, MMP-1 and MMP-3, in human endothelial cells. 935 56

We investigated whether PF4 could regulate the constitutive and thrombin-stimulated expression of metalloproteinases (MMPs) in endothelial cells (EC). PF4 inhibited the increase in the expression of MMP-1 and MMP-3 promoted by thrombin or the thrombin receptor agonist peptide SFLLRNPNDKYEPF (SFLL..) by 50% but did not modify the constitutive expression of these MMPs. This inhibitory effect was not mediated through a direct interaction of PF4 with thrombin or with the MMPs themselves. The interaction of PF4 with heparan sulfates at the surface of the EC appeared to be implicated in the inhibition mechanism of MMP-1 but not in that of MMP-3. MMP-1 transcription levels remained unchanged after PF4 treatment, whereas the increase in MMP-3 transcription induced by thrombin or SFLL.. was inhibited by approximately 50%. Expression of the tissue inhibitors of metalloproteinases TIMP-1 and TIMP-2 was not affected by PF4. The present data provide new evidence that the antiangiogenic properties of PF4 involve the inhibition of matrix breakdown and suggest that this property of PF4 could be especially relevant in the context of thrombin-regulated tissue remodelling.
 ...
PMID:PF4 inhibits thrombin-stimulated MMP-1 and MMP-3 metalloproteinase expression in human vascular endothelial cells. 949 37

Platelet-leukocyte aggregation (PLA) links haemostasis to inflammation. The role of nitric oxide (NO) and matrix metalloproteinases (MMP-1, -2, -3, -9) in PLA regulation was studied. Homologous human platelet-leukocyte suspensions were stimulated with thrombin (0.1-3 nM) and other proteinase activated receptor-activating peptides (PAR-AP), including PAR1AP (0.5-10 microM), PAR4AP (10-70 microM), and thrombin receptor-activating peptide (1-35 microM). PLA was studied using light aggregometry with simultaneous measurement of oxygen-derived free radicals, dual colour flow cytometry, and phase-contrast microscopy. The release of NO was measured using a porphyrinic nanosensor, while MMPs were investigated by Western blot, substrate degradation assays, immunofluorescence microscopy, and flow cytometry. The levels of P-selectin and microparticles (MP) in PLA were measured by flow cytometry. PLA was also characterized using pharmacological agents: S-nitroso-glutathione (GSNO, 0.01-10 microM), 1H-Oxadiazole quinoxalin-1-one (ODQ, 1 microM), N(G)-L-nitro-L-arginine methyl ester (L-NAME, 100 microM) and compounds that modulate the actions of MMPs such as phenanthroline (100 microM), monoclonal anti-MMP antibodies, and purified MMPs. PAR agonists concentration-dependently induced PLA, an effect associated with the release of microparticles (MP) and the translocation of P-selectin to the platelet surface. NO and radicals were also released during PLA. Inhibition of NO bioactivity by the concomitant release of free radicals or by the treatment with L-NAME or ODQ stimulated PLA, while pharmacological administration of GSNO decreased PLA. PAR agonist-induced PLA resulted in the liberation of MMP-1, -2, -3, and -9. During PLA, MMPs were present on the cell surface, as shown by flow cytometry and immunofluorescence. PLA led to the activation of latent MMPs to active MMPs, as shown by Western blot and substrate degradation assays. Inhibition of MMPs actions by phenanthroline and by the antibodies attenuated PLA. In contrast, purified active, but not latent, MMPs amplified thrombin-induced PLA. It is concluded that NO and MMP-1, -2, -3, and -9 play an important role in regulation of PAR agonist-induced PLA.
 ...
PMID:Platelet-leukocyte aggregation induced by PAR agonists: regulation by nitric oxide and matrix metalloproteinases. 1553 89

Many tumor types express matrix metalloproteinase-1 (MMP-1); its collagenase activity facilitates both tumor cell invasion and metastasis. MMP-1 expression is also associated with increased angiogenesis; however, the exact mechanism by which this occurs is not clear. MMP-1 proteolytically activates protease activated receptor-1 (PAR-1), a thrombin receptor that is highly expressed in endothelial cells. Thrombin is also present in the tumor microenvironment, and its activation of PAR-1 is pro-angiogenic. It is currently unknown whether MMP-1 activation of PAR-1 induces angiogenesis in a similar or different manner compared with thrombin. We sought to determine the mechanism by which MMP-1 promotes angiogenesis and to compare the effects of MMP-1 with those of thrombin. Our results demonstrate that via PAR-1, MMP-1 activates mitogen-activated protein kinase signaling cascades in microvessel endothelial cells. Although thrombin activation of PAR-1 also induces signaling through these pathways, the time-course of activation appears to vary. Gene expression analysis revealed a possible consequence of these signaling differences as MMP-1 and thrombin induce expression of different subsets of pro-angiogenic genes. Furthermore, the combination of thrombin and MMP-1 is more angiogenic than either protease alone. These data demonstrate that MMP-1 acts directly on endothelial cells as a pro-angiogenic signaling molecule and also suggest that the effects of MMP-1 may complement the activity of thrombin to better facilitate angiogenesis and promote tumor progression.
 ...
PMID:Matrix metalloproteinase-1 and thrombin differentially activate gene expression in endothelial cells via PAR-1 and promote angiogenesis. 1898 1

Previously we showed that expansion of intracerebral hemorrhage (ICH) into the internal capsule greatly aggravated neurological symptoms in mice. Here we examined ICH-associated events in the internal capsule with relation to neurological dysfunction. Corticospinal axons labeled by biotinylated dextran amine exhibited fragmented appearance after ICH induced by local injection of collagenase into the internal capsule. Fragmentation of axonal structures was confirmed by neurofilament-H immunostaining, which was evident from 6h after induction of ICH. We also observed accumulation of amyloid precursor protein, which indicated compromised axonal transport, from 3h after induction of ICH. The early defect in axonal transport was accompanied by a robust decline in motor performance. Local application of an axonal transport inhibitor colchicine to the internal capsule induced a prompt decline in motor performance, suggesting that compromised axonal transport is closely associated with early neurological dysfunction in ICH. Arrest of axonal transport and fragmentation of axonal structures were also induced by local injection of thrombin, but not by thrombin receptor activator peptide-6, a protease-activated receptor-1 agonist. These results suggest that receptor-independent actions of thrombin mediate disruption of structure and function of axons by hemorrhage expansion into the internal capsule, which leads to severe neurological dysfunction.
...
PMID:Axonal dysfunction in internal capsule is closely associated with early motor deficits after intracerebral hemorrhage in mice. 2651 23