Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.22.56 (caspase-3)
 35,750 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Here, we describe a new function for plasmin and matrix metalloproteinases (MMPs), which is to regulate the regression of capillary tubes in three-dimensional extracellular matrix environments. Using a well-described capillary morphogenesis system in three-dimensional collagen matrices, a new model of capillary regression has been established by adding plasminogen to the culture medium. Plasminogen is converted to plasmin by endothelial cell plasminogen activators which then induces matrix metalloproteinase-dependent collagen gel contraction and capillary regression. Plasminogen addition results in activation of MMP-1 and MMP-9, which then results in collagen proteolysis followed by capillary regression. The endothelial cells undergo apoptosis following gel contraction as detected by flow cytometric analysis as well as by detectable caspase-3 cleavage and caspase-dependent cleavage of the actin cytoskeletal regulatory protein, gelsolin. In addition, directly correlating with the contraction response, tyrosine phosphorylation of p130cas, an adapter protein in the focal adhesion complex, is observed followed by disappearance of the protein. Proteinase inhibitors that block MMPs (TIMP-1 or TIMP-2), plasminogen activators (PAI-1) or plasmin (aprotinin) completely block the gel contraction and regression process. In addition, chemical inhibitors of MMPs that block capillary regression also block MMP-1 and MMP-9 activation suggesting that a key element in this regression response is the molecular control of MMP activation by endothelial cells. Blocking antibodies directed to MMP-1 or MMP-9 interfere with capillary regression while blocking antibodies directed to PAI-1 accelerate capillary regression suggesting that endogenous synthesis of PAI-1 negatively regulates this process. These data present a novel system to study a new mechanism that may regulate regression of capillary tubes, namely, plasmin and MMP-mediated degradation of extracellular matrix.
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PMID:Matrix metalloproteinase-1 and -9 activation by plasmin regulates a novel endothelial cell-mediated mechanism of collagen gel contraction and capillary tube regression in three-dimensional collagen matrices. 1118 Nov 75

Oxidized LDL (oxLDL) may contribute to the accumulation of apoptotic cells in atherosclerotic plaques. Although it is well established in monophasic chemical systems that the highly unsaturated EPA and DHA will oxidize more readily than FA that contain fewer double bonds, our previous studies showed that enrichment of LDL, which has discrete polar and nonpolar phases, with these FA did not increase oxidation. The objective of this study was to compare the extent of apoptosis induced by EPA/DHA-rich oxLDL to that induced by EPA/DHA-non-rich oxLDL in U937 cells. LDL was obtained from one healthy subject three times before and after supplementation for 5 wk with 15 g/d of fish oil (FO), an amount easily obtainable from a diet that contains fatty fish. After supplementation, an EPA/DHA-rich LDL was obtained. Oxidative susceptibility of LDL, as determined by measuring the formation of conjugated dienes and the accumulation of cholesteryl ester hydroperoxides, was not higher in EPA/DHA-rich LDL. The oxLDL-induced cell apoptosis was detected by the activation of caspase-3, the translocation of PS to the outer surface of the plasma membrane using the Annexin V-fluorescein isothiocyanate binding assay, and the presence of chromatin condensation and nuclear fragmentation using the 4,6-diamidino-2-phenylindole staining assay. All three measures showed that after FO supplementation, EPA/DHA-rich oxLDL-induced cell apoptosis decreased. The decrease was not related to the concentration of lipid hydroperoxides. This study suggests that a possible protective effect of EPA/DHA-rich diets on atherosclerosis may be through lessening cell apoptosis in the arterial wall.
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PMID:Enrichment of LDL with EPA and DHA decreased oxidized LDL-induced apoptosis in U937 cells. 1237 50

Eicosapentaenoic acid (EPA; 20:5n-3) may reduce the cell number in cultured leukemia/lymphoma cells owing to reduced cell proliferation, induction of cell death, or a combination of these processes. EPA has been shown to promote apoptosis in Ramos cells, and our present study was focused on a possible cell cycle arrest and the pathways by which the apoptotic process is induced. Apoptosis may proceed along the intrinsic (mitochondrial) or the extrinsic (death receptor) pathway, which are mediated via different caspases. Caspases are a class of homologous cysteine proteases recognized as pivotal mediators of apoptosis. We investigated whether EPA affects progression of the cell cycle or promotes apoptosis directly. By incorporation of [3H]thymidine and [3H]valine, we showed that DNA, as well as protein synthesis, was reduced after incubation of Ramos cells with EPA for 6 h. We monitored cell cycle distribution by 5-bromo-2'-deoxyuridine staining and observed no cell cycle arrest in the EPA-incubated cells. Incubation of cells with EPA caused PS-flipping, as demonstrated by annexin V-binding (flow cytometry), and cleavage of poly(ADP-ribose) polymerase measured by Western blot analysis. Furthermore, we observed increased activity of caspase-3 and -9, but not of caspase-8. Whereas inhibitors of caspase-3 and -9 reduced EPA-induced apoptosis, inhibition of caspase-8 did not. This suggests that EPA may promote apoptosis via the intrinsic pathway in Ramos cells. Thus, the reduction in cell number can be explained by a direct apoptotic effect of EPA rather than via cell cycle arrest.
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PMID:Eicosapentaenoic acid promotes apoptosis in Ramos cells via activation of caspase-3 and -9. 1237 51

Cartilage loss in osteoarthritis is characterized by cartilage degradation and chondrocyte death. Cartilage degradation is induced by activation of matrix-metalloproteinases (MMPs) activity and degradation of glycosaminoglycan (GAG) and collagen. Also, chondrocyte death is induced by the apoptosis through the activation of MAP kinase and caspases activities. On the basis of this background, our study was designed to examine the cartilage protective and anti-apoptotic effect of Aralia cordata. Cartilage explants and Chondrocytes were cultured from rabbit knee joint cartilage and treated by 5 ng/ml IL-1alpha. Cartilage and chondroprotective effects of Aralia cordata were determined by measuring (1) GAG and collagen expression, (2) GAG and collagen degradation, (3) TIMP and MMPs expression, and (4) TIMP and MMPs activity. Anti-apoptotic effects of Aralia cordata were determined by measuring (1) JNK and p38 MAP kinase expression, (2) apoptotic cells by flow cytometry, and (3) caspase-3 activity. In cartilage explants and chondroctyes treated by IL-1alpha, Aralia cordata showed the decrease of GAG and collagen degradation, decrease of MMPs (MMP-1, -3, -13) activity, and increase of TIMP-1 activity in a dose-dependent manner. Aralia cordata also showed anti-apoptotic effect by inhibition of early and late apoptotic cells, sub-G1 phase cells, and caspase-3 activity through the downregulation of JNK and p38 MAP kinase signaling pathway. Aralia cordata inhibited the cartilage and chondrocyte destruction through the downregulation of MMPs activities and the inhibition of proteoglycan and collagen degradation. Also, Aralia cordata inhibited the chondrocyte apoptosis through the downregulation of JNK and p38 MAP kinase signal, and the inhibition of caspase-3 activity.
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PMID:Effect of Aralia cordata extracts on cartilage protection and apoptosis inhibition. 1681 82

Besides its matrix metalloproteinases inhibitory activity, TIMP-1 exhibits other biological activities such as cell survival and proliferation. The intracellular signalling pathway elicited by TIMP-1 begins to be elucidated. We have shown previously that the caspase-3 and the p38alpha MAP kinase were activated during TIMP-1-induced UT-7 cells erythroid differentiation. In this study, we demonstrated that TIMP-1 differentiating effect can be extended to the IL-3-dependent myeloid murine 32D cell line and human erythroid progenitors derived from cord blood CD34(+) cells. By performing small interfering RNA transfection and using chemical inhibitors, we evidenced that caspase-3 was involved in TIMP-1 differentiating effect. We then identified the MEKK1 kinase as a caspase-3 substrate and demonstrated that the MEKK1/MEK6/p38alpha pathway was activated downstream the caspase-3 in TIMP-1-induced hematopoietic differentiation.
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PMID:Tissue inhibitor of metalloproteinase-1 promotes hematopoietic differentiation via caspase-3 upstream the MEKK1/MEK6/p38alpha pathway. 1730 22

Keratoconus is a disease in which the central cornea becomes thinned. This could result from corneal stromal cell apoptosis or be induced or perpetuated by the activation of matrix degrading enzymes, particularly members of the matrix metalloproteinase (MMP) family. In some circumstances, the MMP inhibitors TIMP-1 and TIMP-3 exhibit anti-apoptotic and pro-apoptotic properties, respectively. Because they potentially influence keratoconus progression, the effects of TIMP-1 and TIMP-3 on stromal cell viability were investigated. The TIMP-1 and TIMP-3 proteins were over-expressed in cultured corneal stromal cells by using the adenoviral vectors RAdTIMP-1 and RAdTIMP-3 and quantified by enzyme-linked immunosorbant assay (ELISA). Apoptotic cells were detected by TUNEL and caspase-3 activity. The anti-apoptotic effects of TIMP-1 were investigated by co-infecting it with RAdTIMP-1 and RAdTIMP-3 and by adding TIMP-1 protein to stromal cell cultures prior to infecting them with RAdTIMP-3. Immunohistochemistry was used to localise and determine relative numbers of apoptotic and TIMP producing stromal cells in sections of normal and keratoconic corneas. The results showed that over-expression of TIMP-3 induced apoptosis in corneal stromal cell cultures. Up-regulated TIMP-1 production or the addition of exogenous TIMP-1 protein prevented stromal cell overgrowth, changed stromal cell morphology and reduced the extent of TIMP-3 induced apoptosis. Localised relative concentrations of TIMP-1/TIMP-3 could thus determine whether these cells remain viable or become apoptotic. This may be relevant to the keratoconic condition since significantly more apoptotic cells were identified in the anterior stroma of keratoconic corneas than normal corneas and the majority of theTIMP-1 and TIMP-3 producing stromal cells were also located in this region.
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PMID:Changes in the balance of the tissue inhibitor of matrix metalloproteinases (TIMPs)-1 and -3 may promote keratocyte apoptosis in keratoconus. 1744 31

Neuronal apoptosis is involved in neurodegenerative diseases such as Alzheimer's disease and Parkinson.s disease. An efficient means of preventing it remains to be found. Some n-3 polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA, 22 : 6n-3) and eicosapentaenoic acid (EPA, 20 : 5n-3) have been reported to be protective against the neuronal apoptosis and neuronal degeneration seen after spinal cord injury (SCI) [1]. However, it is unclear which kinds of PUFAs have the most potent ability to inhibit neuronal apoptosis and whether the simultaneous treatment of PUFAs inhibits the apoptosis. In the present study, we compared the abilities of various n-3- and n-6- PUFAs to inhibit the apoptosis induced after the administration of different apoptotic inducers, etoposide, okadaic acid, and AraC, in mouse neuroblastoma cells (Neuro2a). Preincubation with DHA (22 : 6n-3), eicosapentaenoic acid (EPA, 20 : 5n-3), alpha-linolenic acid (alpha-LNA, 18 : 3n-3), linoleic acid (LA, 18 : 2n-6), arachidonic acid (AA, 20 : 4n-3), and gamma-linolenic acid (gamma-LNA, 18 : 3n-6) significantly inhibited caspase-3 activity and LDH leakage but simultaneous treatment with the PUFAs had no effect on the apoptosis of Neuro2a cells. There were no significant differences of the anti-apoptotic eff ect among the PUFAs. These results suggest that PUFAs may not be effective for inhibiting neuronal cell death after acute and chronic neurodegenerative disorders. However, dietary supplementation with PUFAs may be beneficial as a potential means to delay the onset of the diseases and/or their rate of progression.
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PMID:Inhibitory effect of polyunsaturated fatty acids on apoptosis induced by etoposide, okadaic acid and AraC in Neuro2a cells. 1759 50

Enzastaurin (LY317615.HCI), a protein kinase C (PKC)-beta inhibitor, has a radiosensitising effect on 4T1 murine breast cancer and human glioma cells; however, the exact mechanism of this action has not been evaluated. The present study investigated the effects of enzastaurin and gamma irradiation on PKC activity in MCF-7 human breast cancer cells in vitro and in vivo. Enzastaurin (5 microM) in combination with irradiation (2-8 Gy) produced a synergistic decline in MCF-7 clonogenic cell survival. Analysis of MCF-7 cells stained with Annexin V and 7-aminoactinomycin D showed a dose-dependent increase in apoptosis in response to enzastaurin (3, 5 and 7 microM) and irradiation (10 Gy) compared to irradiation alone. This pro-apoptotic effect was confirmed by increases in caspase-3 and -9 activity. In a MCF-7 xenograft model, irradiation with 25 Gy increased PKC-alpha activity by 2.5-fold compared to untreated controls, whereas PKC-epsilon and -betaII activity was increased by 1.8-fold. Radiation-induced activation of all three anti-apoptotic isoforms of PKC was reversed by pre-treatment with enzastaurin (75 mg/kg, twice daily for 3 days). We conclude that enzastaurin has a radiosensitising effect on MCF-7 human xenograft tumours through the reversal of anti-apoptotic activation of PKC isoforms.
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PMID:Enzastaurin renders MCF-7 breast cancer cells sensitive to radiation through reversal of radiation-induced activation of protein kinase C. 1844 27

Reactive oxygen and nitrogen species (ROS and RNS, respectively) generate nitrotyrosine and activate latent resident myocardial matrix metalloproteinases (MMPs). Although in chronic heart failure (CHF) there is robust increase in ROS, RNS, and MMP activation, recent data suggest that hydrogen sulfide (H(2)S, a strong antioxidant gas) is cardioprotective. However, the role of H(2)S in mitigating oxidative and proteolytic stresses in cardiac remodeling/apoptosis in CHF was unclear. To test the hypothesis that H(2)S ameliorated cardiac apoptosis and fibrosis by decreasing oxidative and proteolytic stresses, arteriovenous fistula (AVF) was created in wild-type (C57BL/6J) mice. The hearts were analyzed at 0, 2, and 6 wk after AVF. To reverse the remodeling, AVF mice were treated with NaHS (an H(2)S donor, 30 micromol/l in drinking water) at 8 and 10 wk. The levels of MMPs were measured by gelatin-gel zymography. The levels of nitrotyrosine, tissue inhibitors of metalloproteinase (TIMPs), beta(1)-integrin, and a disintegrin and metalloproteinase-12 (ADAM-12) were analyzed by Western blots. The levels of pericapillary and interstitial fibrosis were identified by Masson trichrome stains. The levels of apoptosis were measured by identifying the TdT-mediated dUTP nick end labeling (TUNEL)-positive cells and caspase-3 levels. The results suggested robust nitrotyrosine and MMP activation at 2 and 6 wk of AVF. The treatment with H(2)S donor mitigated nitrotyrosine generation and MMP activation (i.e., oxidative and proteolytic stresses). The levels of TIMP-1 and TIMP-3 were increased and TIMP-4 decreased in AVF hearts. The treatment with H(2)S donor reversed this change in TIMPs levels. The levels of ADAM-12, apoptosis, and fibrosis were robust and integrin were decreased in AVF hearts. The treatment with H(2)S donor attenuated the fibrosis, apoptosis, and decrease in integrin.
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PMID:H2S ameliorates oxidative and proteolytic stresses and protects the heart against adverse remodeling in chronic heart failure. 1993 16

Evidence suggests a link between Parkinson's disease and the dietary intake of omega (n)-3 and n-6 polyunsaturated fatty acids (PUFAs). Presently, we investigated whether an acute dose of parkinsonian neurotoxin 1-methyl-4-phenylpyridinium (MPP(+)) affects brain n-3 and n-6 PUFA content and expression of fatty acid metabolic enzymes cytosolic phospholipase A2 (cPLA2) and cyclooxygenase-2 (COX-2) in brain slices from C57Bl/6 mice. Furthermore, we investigated whether feeding a diet of n-3 PUFA ethyl-eicosapentaenoate (E-EPA) to these mice can attenuate the MPP(+) induced changes in brain PUFA content and expression of cPLA2 and COX-2, and attenuate MPP(+) induced changes in neurotransmitters and metabolites and apoptotic markers, bax, bcl-2 and caspase-3. MPP(+) increased brain content of n-6 PUFAs linoleic acid and arachidonic acid, and increased the mRNA expression of cPLA2. MPP(+) also depleted striatal dopamine levels and increased dopamine turnover, and depleted noradrenaline levels in the frontal cortex. The neurotoxin induced increases in bax, bcl-2 and caspase-3 mRNA expression that approached significance. E-EPA by itself increased brain n-3 content, including EPA and docosapentaenoic acid (C22:5, n-3), and increased cortical dopamine. More importantly, E-EPA attenuated the MPP(+) induced increase in n-6 fatty acids content, partially attenuated the striatal dopaminergic turnover, and prevented the increases of pro-apoptotic bax and caspase-3 mRNAs. In conclusion, increases in n-6 PUFAs in the acute stage of exposure to parkinsonian neurotoxins may promote pro-inflammatory conditions. EPA may provide modest beneficial effects in Parkinson's disease, but further investigation is warranted.
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PMID:Ethyl-eicosapentaenoate modulates changes in neurochemistry and brain lipids induced by parkinsonian neurotoxin 1-methyl-4-phenylpyridinium in mouse brain slices. 2086 57


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