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

Analyses using either one or two-dimensional gel electrophoresis were performed to identify the contribution of several proteases to lower molecular weight (MW) neurofilament 68 (NF68) break down products (BDPs) detected in cortical homogenates following unilateral cortical impact injury in rats. One dimensional immunoblot of BDPs obtained from in vitro cleavage of enriched neurofilaments (NF) by purified micro-calpain, m-calpain, cathepsin, B, cathepsin D, and CPP32 (caspase-3) were compared to in vivo samples from rats following traumatic brain injury (TBI). Comparison of these blots provided information on the relative contribution of different cysteine or aspartic proteases to NF loss following brain injury. As early as 3 hrs post-injury, cortical impact resulted in the presence of several lower MW NF68 immunopositive bands having patterns similar to those previously reported to be produced by calpain mediated proteolysis of neurofilaments. Only micro-calpain and m-calpain in vitro digestion of enriched neurofilaments contributed to the presence of the low MW 57 kD NF68 break down product (BDP) detected in post-TBI samples. Cathepsin B, cathepsin D, and caspase-3 failed to produce either the 53 kD or 57 kD NF BDPs. Further, 1 and 2 dimensional peptide maps containing a 1:1 ratio of in vivo and in vitro tissue samples showed complete comigration of lower MW immunopositive spots produced by TBI or in vitro incubation with m-calpain, thus providing additional evidence for the potential role of calpain activation to the production of NF68 BDPs following TBI. More importantly, 2-dimensional gel electrophoresis detected that immunopositive NF68 spots shifted to the basic pole (+) suggesting that dephosphorylation of the NF68 subunit pool may be associated with NF protein loss following TBI, an observation not previously noted in any model of experimental brain injury.
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PMID:Immunoblot analyses of the relative contributions of cysteine and aspartic proteases to neurofilament breakdown products following experimental brain injury in rats. 980 82

The purposes of this experiment were (1) to determine if apoptosis was accelerated during formation of selenite cataract, and (2) to determine the role of calpains and caspases in lens apoptosis. Evidence for apoptosis in selenite-injected rats included: approximately 7-8% of epithelial cells in germinative zone were positive, disappearance of the nuclear membrane, condensation of the chromatin, and breakdown of PARP. Activation of calpains was indicated by characteristic limited proteolysis of crystallins, breakdown of alpha-spectrin to 150/145 kDa fragments, hydrolysis of vimentin, and autolytic breakdown of m-calpain. Selenite cataract did not have an appreciable effect on the mRNA levels for caspase-3, calpains, and calpastatin. This indicated the increased enzyme activity of m-calpain and caspase-3 in selenite cataract occurred at the enzyme level rather than by upregulation of mRNAs. Increased calpain and caspase activity may be linked to the selenite-induced apoptosis. Such data are important because they indicate that apoptosis may be a fairly early event in selenite cataract.
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PMID:Evidence for apoptosis in the selenite rat model of cataract. 1096 62

Testicular torsion requires emergent release of the twisted spermatic cord. Ischemia/reperfusion (I/R) plays an important role in its pathogenesis, and recent data suggest that germ cells undergo apoptosis during I/R. In a model of torsion/detorsion (i.e., I/R) of the rat testis, involvement of calpain and caspase in necrotic and apoptotic cell death was examined. After 1 h of ischemia followed by 0, 0.5, 1, 6, or 24 h of reperfusion, the germ cells positively stained with in situ TUNEL, and DNA fragmentation, activation of caspase-3, and proteolysis of caspase substrates increased with time of reperfusion, demonstrating apoptosis. In addition, m-calpain activation and proteolysis of alpha-fodrin were increased during reperfusion, and its activation is thought to be involved in the necrosis. A calpain inhibitor, acety-leucyl-leucyl-norleucinal, inhibited the phenomena associated with apoptosis and necrosis induced by I/R, although a caspase inhibitor, Z-Val-Ala-Asp-fluoromethlyketone, only inhibited apoptotic changes. The inhibition of calpain but not caspase ameliorated the injury after 60 days of reperfusion following 1 h of ischemia. The calpain inhibitor injected just before reperfusion effectively suppressed alpha-fodrin proteolysis, suggesting its usefulness in the treatment of testicular torsion.
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PMID:Inhibition of calpain but not caspase protects the testis against injury after experimental testicular torsion of rat. 1105 63

The relative contributions of apoptosis and necrosis in brain injury have been a matter of much debate. Caspase-3 has been identified as a key protease in the execution of apoptosis, whereas calpains have mainly been implicated in excitotoxic neuronal injury. In a model of unilateral hypoxia-ischemia in 7-day-old rats, caspase-3-like activity increased 16-fold 24 h postinsult, coinciding with cleavage of the caspase-3 proenzyme and endogenous caspase-3 substrates. This activation was significantly decreased by pharmacological calpain inhibition, using CX295, a calpain inhibitor that did not inhibit purified caspase-3 in vitro. Activation of caspase-3 by m-calpain, but not mu-calpain, was facilitated in a dose-dependent manner in vitro by incubating cytosolic fractions, containing caspase-3 proform, with calpains. This facilitation required the presence of some active caspase-3 and could be abolished by including the specific calpain inhibitor calpastatin. This indicates that initial cleavage of caspase-3 by m-calpain, producing a 29-kDa fragment, facilitates the subsequent cleavage into active forms. This is the first report to our knowledge suggesting a direct link between the early, excitotoxic, calcium-mediated activation of calpain after cerebral hypoxia-ischemia and the subsequent activation of caspase-3, thus representing a tentative pathway of "pathological apoptosis."
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PMID:Synergistic activation of caspase-3 by m-calpain after neonatal hypoxia-ischemia: a mechanism of "pathological apoptosis"? 1112 42

Gas2 is a caspase-3 substrate that plays a role in regulating microfilament and cell shape changes during apoptosis. Here we provide evidence that overexpression of Gas2 efficiently increases cell susceptibility to apoptosis following UV irradiation, etoposide and methyl methanesulfonate treatments, and that these effects are dependent on increased p53 stability and transcription activity. To investigate possible pathways linking Gas2 to p53, a yeast two-hybrid screen swas performed, indicating m-calpain as a strong Gas2- interacting protein. Moreover, we demonstrate that Gas2 physically interacts with m-calpain in vivo and that recombinant Gas2 inhibits calpain-dependent processing of p53. Importantly, the Gas2 dominant-negative form (Gas2171-314) that binds calpain but is unable to inhibit its activity abrogates Gas2's ability to stabilize p53, to enhance p53 transcriptional activity and to induce p53-dependent apoptosis. Finally, we show that Gas2 is able to regulate the levels of p53 independently of Mdm2 status, suggesting that, like calpastatin, it may enhance p53 stability by inhibiting calpain activity.
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PMID:The death substrate Gas2 binds m-calpain and increases susceptibility to p53-dependent apoptosis. 1138 5

Calpain, a calcium-activated cysteine protease, has been implicated in neuronal degeneration and death. In this study, we have characterized calpain activation in adult rat cerebral cortex and cerebellum, using an experimental paradigm of in vivo chronic ethanol exposure. Ethanol treatment increased the calpain activity in cortex and cerebellum, but to a higher extent in the cortex. Western blot analysis revealed a significant decrease in m-calpain levels while calpastatin levels were unaltered. Calpain activation was further monitored by the proteolysis of alpha-spectrin (fodrin) and protein kinase C-alpha (PKC-alpha). Protease specific spectrin breakdown products revealed calpain generated 150- and 145-kDa fragments. In addition, we also observed a 120-kDa fragment characteristic of caspase-3 activation in the cerebellum. PKC-alpha levels were decreased in the cortex and cerebellum by ethanol. Calpain activation, cleavage of alpha-spectrin into calpain specific signature fragments and decreased PKC-alpha protein levels after ethanol treatment provide the evidence of calpain involvement besides caspase-3-mediated cell death in the cortex and cerebellum. Given the role of calpains in cell death, increased calpain activity followed by alpha-spectrin cleavage in this study suggests that calpains are important effectors in ethanol-mediated cell injury and alcoholic neurodegeneration.
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PMID:Calpain activation and alpha-spectrin cleavage in rat brain by ethanol. 1188 Feb 3

Under physiological conditions, manganese(II) exhibits catalase-like activity. However, at elevated concentrations, it induces apoptosis via a non-mitochondria-mediated mechanism (Oubrahim, H., Stadtman, E. R., and Chock, P. B. (2001) Proc. Natl. Acad. Sci. U. S. A. 98, 9505-9510). In this study, we show that the Mn(II)-induced apoptosis, as monitored by caspase-3-like activity, in NIH3T3 cells was inhibited by calpain inhibitors I and II or the p38 MAP kinase inhibitor, SB202190. The control experiments showed that each of these inhibitors in the concentration ranges used exerted no effect on activated caspase-3-like activity. Furthermore, caspase-12 was cleaved in Mn(II)-treated cells, suggesting that the Mn(II)-induced apoptosis is mediated by caspase-12. This notion is confirmed by the observations that pretreatment of NIH3T3 cells with either caspase-12 antisense RNA or dsRNA corresponding to the full-length caspase-12 led to a dramatic decrease in caspase-3-like activity induced by Mn(II). The precise mechanism by which Mn(II) induced the apoptosis is not clear. Nevertheless, Mn(II), in part, exerts its effect via its ability to replace Ca(II) in the activation of m-calpain, which in turn activates caspase-12 and degrades Bcl-xL. In addition, the dsRNA(i) method serves as an effective technique for knocking out caspase-12 in NIH3T3 cells without causing apoptosis.
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PMID:Manganese(II) induces apoptotic cell death in NIH3T3 cells via a caspase-12-dependent pathway. 1196 91

Decreased susceptibility to apoptosis and impaired proliferative control are thought to be responsible for prolonged life span and accumulation of chronic lymphocytic leukemia (B-CLL) cells. The activity of calpains (calcium-dependent, neutral proteases, active in the cells responding to signals inducing a rise of cytoplasmic Ca(++)) is involved in the regulation of apoptosis of some cell types by interaction with caspase-3. This work verifies the hypothesis of the abnormal activity of calpains and its role in reduced apoptosis of the B-CLL cells. Casein zymography, reverse transcriptase-polymerase chain reaction, and Western blotting were used for identification and quantification of the activity and expression of calpains in B-CLL cells and purified normal B lymphocytes. The activity and expression of mu-calpain (requiring micromolar Ca(++) for activation) are significantly higher in the leukemic than in nonmalignant cells. Contrarily, the activity and expression of m-calpain (requiring millimolar Ca(++)) as well as the expression of calpastatin (an endogenous inhibitor of calpains) are unchanged or reduced in the B-CLL lymphocytes. Correspondingly, the activity of caspase-3 is many times lower in the B-CLL cells than in normal B lymphocytes. Inhibition of overexpressed mu-calpain in living B-CLL cells in vitro results in doubling of the proportion of the cells undergoing spontaneous apoptosis. This observation suggests a possible role for calpains in longer survival of the B-CLL cells and may open new therapeutic possibilities.
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PMID:Modulation of the activity of calcium-activated neutral proteases (calpains) in chronic lymphocytic leukemia (B-CLL) cells. 1217 3

Transforming growth factor beta1 (TGF-beta(1)) is regarded as an important auto/paracrine regulator of mammary gland involution, however, its apoptotic effect and inhibition of growth in bovine mammary epithelial cells (MEC) has not been documented. In the present study, laser scanning cytometry, confocal and immunoelectron microscopy techniques were used for quantitative and qualitative analyzes of apoptosis, cell cycle and expression, subcellular redistribution and interactions of apoptosis-related proteins in bovine BME-UV1 MEC exposed to TGF-beta(1). TGF-beta(1) exerted both antiproliferative and apoptotic action. The antiproliferative effect was manifested by increase of cell number in G1 phase with simultaneous decrease of cell number in S and G2/M phases. It resulted in significant increase of G1/S ratio in TGF-beta(1) treated cells, indicating partial cell cycle arrest at the G1-S transition. Apoptosis induced by TGF-beta(1) manifested by characteristic morphological changes. Among biochemical features of TGF-beta(1)-induced apoptosis in BME-UV1 cells we found: (1) an increase of cell number with lowered DNA content and condensed chromatin, (2) enhanced expression of caspase-3 and m-calpain, (3) elevated number of 89 kDa PARP degradation fragments, and (4) aggregation of Bax and its interactions with voltage dependant anion channel-1. In conclusion, antiproliferative and apoptotic action of TGF-beta(1), observed in the culture of BME-UV1 cells, suggests an essential role of this cytokine in the regulation of mammary gland involution in cow.
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PMID:Antiproliferative and apoptotic effect of TGF-beta 1 in bovine mammary epithelial BME-UV1 cells. 1272 91

The molecular mechanism of the cell death-promoting effect of dexamethasone (Dex) was studied during myogenesis (10 days) in L6 muscle cells by making use of several indices such as cell viability (protein synthesis, mitochondrial respiration), mortality (DNA fragmentation, chromatin condensation, structural modifications) and immunocytochemical studies [hydrogen peroxide, m-calpain (calpain 2)]. Dex initially (2 nM) stimulated protein synthesis (P < 0.001), but a further increase (20 nM) did not stimulate, whereas a higher dose (200 nM) inhibited formation of cellular proteins (P < 0.001). The latter, apparently, resulted from impaired cell viability (P < 0.001). From the day 4, structural changes featuring cell death were observed. Antioxidants [sodium ascorbate (ASC), catalase (CAT) or N-acetyl-L-cysteine (NAC)] as well as the inhibition of transcription and translation by actinomycin D abrogated Dex-induced cell death (P < 0.001). Using a fluorescent probe (DCFH-DA) we directly corroborated the working hypothesis of the mediating role of H2O2 in the reduction of cell viability by the excess of glucocorticoids. We also found that tPKC, PLCgamma, PLA2 were required to induce Dex-dependent cell death since inactivation of tPKC by H7 completely abolished the cytotoxic effect of Dex, while the blockade of PLCgamma and PLA2 by U 73122 partially abolished the effect. Cell death was triggered by Ca2+ influx necessary to activate m-calpain since it was reversed by the calcium chelator EGTA or m-calpain inhibitor ALLN but not EDTA nor ALLM. However, cell viability impaired by Ca2+ ionophore A 23187 (P < 0.001) was neither reversed by EGTA, nor EDTA, nor caspase-3 blocker--Ac DEVD CHO, nor ALLN, nor antioxidants--ASC, NAC, CAT. Specific caspase-3 inhibitor Ac DEVD CHO also did not rescue cells from Dex-induced cell death (P < 0.001), in contrast to m-calpain inhibitor--ALLN. Taken together, these findings suggest that reactive oxygen species inhibit protein synthesis and amplify m-calpain-dependent proteolysis. The events that led to the death of L6 muscle cells most likely resulted from Dex-mediated repression of antioxidative defences on the genomic level.
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PMID:Delineation of signalling pathway leading to antioxidant-dependent inhibition of dexamethasone-mediated muscle cell death. 1295 35


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