Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P42574 (caspase-3)
 45,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of melatonin on age-related thymic involution and apoptosis induced by hydroxyl radicals (*OH) in mouse thymocyte cultures was investigated. Exogenous melatonin was administered in the drinking water (15 microg/mL) of 7-month-old male Balb/c mice for 40 consecutive days. Our results show that melatonin distinctly reversed the age-related thymic involution as revealed by the notable increase of cellular density, particularly the number of thymocytes, percentage of thymocytes at G2+S phases and the younger morphological appearance as a whole when compared with control animals. More strikingly, the recovery of these morphometric parameters were maintained for 30 days after the termination of melatonin administration suggesting that the re-established homeostasis by melatonin may last for a longer time. At the same time, when primary culture of thymocytes was preincubated with 200 microM melatonin before their exposure to hydroxyl radicals (*OH) generated by Fe(2+)-mediated Fenton reaction, apoptotic cell death induced by *OH was almost completely prevented as determined by both flow cytometric analysis and the TUNEL assay. DNA laddering assay also documented the inhibition of thymocyte apoptosis by melatonin. Furthermore, we found that the *OH-induced increment of caspase-3 activity in thymocytes was completely abolished by melatonin preincubation. Taken together, our study indicates that in addition to other mechanisms, melatonin may also directly act as an antioxidant via attenuating apoptotic thymocyte death caused by free radicals and stimulates thymocyte proliferation in thymus and thus to rejuvenate the degenerative organ.
J Pineal Res 2001 Oct
PMID:Rejuvenation of degenerative thymus by oral melatonin administration and the antagonistic action of melatonin against hydroxyl radical-induced apoptosis of cultured thymocytes in mice. 1158 55

In the present study, we investigated whether melatonin would prevent nitric oxide (NO)-induced apoptotic death of PGT-beta immortalized pineal cells. To examine the protective effect of melatonin, cytotoxicity assay, DNA fragmentation analysis, caspase-3 activity assay, and Western blotting for caspase-3 and poly(ADP-ribose) polymerase (PARP) were performed. Treatment of cells with S-nitroso-N-acetylpenicillamine (SNAP), an NO donor, was shown to induce apoptotic cell death in a dose-dependent manner, and pretreatment with melatonin (0.1 mm) attenuated the occurrence of NO-induced apoptotic cell death. DNA fragmentation in response to NO was also arrested by melatonin. Caspase-3 activity induced by NO was decreased with melatonin treatment. Furthermore, the active fragments of caspase-3 and PARP were almost completely absent following exposure to melatonin. To elucidate the protective mechanisms of action of melatonin, Western blot analyses for Bcl-2 expression and cytochrome c release were carried out. Pretreatment with melatonin (0.1 mm) induced the expression of Bcl-2 and suppressed the release of cytochrome c into the cytosol, thereby arresting NO-induced apoptotic cell death. These results suggest that the antiapoptotic effect of melatonin is associated with induction of Bcl-2 expression in PGT-beta cells, which in turn blocks caspase-3 activation and inhibits cytochrome c release into the cytosol.
J Pineal Res 2002 Oct
PMID:Melatonin suppresses NO-induced apoptosis via induction of Bcl-2 expression in PGT-beta immortalized pineal cells. 1222 Mar 28

Accumulation of delta-aminolevulinic acid (ALA), as it occurs in acute intermittent porphyria (AIP), is the origin of an endogenous source of reactive oxygen species (ROS), which can exert oxidative damage to cell structures. In the present work we examined the ability of different antioxidants to revert ALA-promoted damage, by incubating mouse astrocytes with 1.0 mM ALA for different times (1-4 hr) in the presence of melatonin (2.5 mM), superoxide dismutase (25 units/mL), catalase (200 units/mL) or glutathione (0.5 mM). The defined relative index [(malondialdehyde levels/accumulated ALA) x 100], decreases with incubation time, reaching values of 76% for melatonin and showing that the different antioxidants tested can protect astrocytes against ALA-promoted lipid peroxidation. Concerning porphyrin biosynthesis, no effect was observed with catalase and superoxide dismutase whereas increases of 57 and 87% were obtained with glutathione and melatonin, respectively, indicating that these antioxidants may prevent the oxidation of porphobilinogen deaminase, reactivating so that the AIP genetically reduced enzyme. Here we showed that ALA induces cell death displaying a pattern of necrosis. This pattern was revealed by loss of cell membrane integrity, marked nuclear swelling and double labeling with annexin V and propidium iodide. In addition, no caspase 3-like activity was detected. These findings provide the first experimental evidence of the involvement of ALA-promoted ROS in the damage of proteins related to porphyrin biosynthesis and the induction of necrotic cell death in astrocytes. Interestingly, melatonin decreases the number of enlarged nuclei and shows a protective effect on cellular morphology.
J Pineal Res 2003 Aug
PMID:Necrotic cell death induced by delta-aminolevulinic acid in mouse astrocytes. Protective role of melatonin and other antioxidants. 1282 7

Activation of K(+) current plays a critical role in the control of programmed cell death. In the present study, whole-cell patch-clamp recording, a caspase-3 activity assay, and flow cytometric analysis were used to examine the effects of the MT2 melatonin receptor agonist 2-iodomelatonin on the delayed-rectifier K(+) current (IK) and the prevention of apoptosis. It was found that apoptosis of cerebellar granular neurons induced by low-K(+) (5 mm) incubation was associated with an increase in IK amplitude and caspase-3 activity. After 6 hr of low-K(+) treatment, IK was increased by 45% (n = 86). Flow cytometry showed that the apoptosis rate increased by 333% compared with the control neurons. In addition, exposure of cultured granule cells to low K(+) also resulted in a significant activation of caspase-3, by 466%. 2-Iodomelatonin (10 microm in injection pipette) inhibited the IK amplitude recorded from control cells and from cells undergoing apoptosis. However, 2-iodomelatonin only modified the IK-channel activation kinetics of cells under both conditions. Furthermore, 2-iodomelatonin reduced the rate of apoptosis and caspase-3 activation, by 66 and 64%, respectively. The melatonin receptor antagonist, 4P-PDOT, abrogated the effect of 2-iodomelatonin on the IK augmentation, caspase-3 activity, and apoptosis. These results suggest that the neuroprotective effects of melatonin are not only because of its function as a powerful antioxidant, but also to its interactions with specific receptors. The effect of 2-iodomelatonin against apoptosis may be mediated by activating a melatonin receptor, which modulates IK channels and reduces K(+) efflux.
J Pineal Res 2004 Mar
PMID:Melatonin receptor agonist 2-iodomelatonin prevents apoptosis of cerebellar granule neurons via K(+) current inhibition. 1496 62

1-Methyl-4-phenylpyridinium (MPP(+)) ion, a toxic metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, is produced by monoamine oxidase B in astrocytes. MPP(+) causes a selective dopaminergic neurodegeneration, the pathophysiologic hallmark of Parkinson disease. However, the toxic effect of MPP(+) on astrocytes remains unclear. Here, we examined the effect of MPP(+) on human astrocytoma U373MG cells, with particular attention to the temporal interaction of glutathione (GSH) and reactive oxygen species (ROS) (H2O2 and O). MPP(+) induced astrocyte apoptosis in a dose-dependent manner 48 hr after treatment. Distinctive early (<6 hr) and late (24-48 hr) responses were observed. ROS production and the oxidized GSH (GSSG)/GSH ratio, indicators of oxidative stress, rose dramatically after 24 hr of MPP(+) exposure, whereas the H2O2 level transiently decreased at 6 hr. ROS overproduction and GSH dysfunction were concomitantly associated with caspase-3 activation and finally led to cell apoptosis. Moreover, GSH depletion by diethyl maleate, but not buthionine sulfoximine, caused cells to die quickly and potentiated the cytotoxicity of MPP(+). Co-treatment with melatonin, a known antioxidant secreted by the pineal gland, significantly prevented cell apoptosis by inhibiting oxidative stress and caspase-3 activation, but it did not affect that the early changes due to MPP(+) treatment. Our results demonstrate that in astrocytes, GSH is involved in the early decrease and late increase in ROS levels induced by MPP(+) treatment. Melatonin remedies the dysfunction of GSH system to block caspase-3 activation and cell apoptosis induced by oxidative stress during the long-term exposure of MPP(+).
J Pineal Res 2004 Mar
PMID:Effect of melatonin on temporal changes of reactive oxygen species and glutathione after MPP(+) treatment in human astrocytoma U373MG cells. 1496 63

The effects of i.p. melatonin (4 + 4 mg/kg, after induction of ischemia and at reperfusion onset) administered either alone or in combination with the thrombolytic tissue-plasminogen activator (t-PA, 10 mg/kg), on cerebral laser Doppler flow (LDF) and ischemic injury were studied after 30 min of middle cerebral artery (MCA) thread occlusion in male C57BL/6 mice. Thread occlusions resulted in reproducible focal ischemias, followed by hyperperfusion reactions immediately after thread withdrawal, as revealed by LDF measurements. Compared with animals receiving normal saline (peak LDF after reperfusion: 172.0 +/- 24.2%), postischemic LDF was significantly attenuated in animals treated with melatonin (105.1 +/- 6.7%, P < 0.05). Delivery of t-PA (132.8 +/- 22.3%) or t-PA plus melatonin (164.7 +/- 36.7%), on the contrary, did not influence postischemic LDF recordings. Twenty-four hours after reperfusion, melatonin treated mice had significantly increased neuronal survival and decreased disseminate cell injury in the ischemia-vulnerable striatum, as investigated by cresyl violet and terminal transferase biotinylated-dUTP nick end labeling stainings. The protective effects were associated with inhibition of caspase-3 activity. Melatonin administration also increased neuronal survival after 30 min MCA occlusion in animals treated with t-PA, although t-PA itself already decreased the degree of injury in a significant manner. Our data demonstrate that melatonin reduces disseminated neuronal injury in the striatum after mild focal ischemia. Brain protection is independent of hemodynamic changes and involves inhibition of caspase-3.
J Pineal Res 2004 Apr
PMID:Melatonin reduces disseminate neuronal death after mild focal ischemia in mice via inhibition of caspase-3 and is suitable as an add-on treatment to tissue-plasminogen activator. 1500 7

Oxidative stress-induced mitochondrial dysfunction has been shown to play a crucial role in the pathogenesis of a wide range of diseases. Protecting mitochondrial function, therefore, is vital for cells to survive during these disease processes. In this study, we demonstrate that melatonin, a chief secretory product of the pineal gland, readily rescued mitochondria from oxidative stress-induced dysfunction and effectively prevented subsequent apoptotic events and death in rat brain astrocytes (RBA-1). The early protection provided by melatonin in mitochondria of intact living cells was investigated by the application of time-lapse conventional, confocal, and multiphoton fluorescent imaging microscopy coupled with noninvasive mitochondria-targeted fluorescent probes. In particular, we observed that melatonin effectively prevented exogenously applied H2O2-induced mitochondrial swelling in rat brain astrocytes at an early time point (within 10 min) and subsequently reduced apoptotic cell death (150 min later). Other early apoptotic events such as plasma membrane exposure of phosphatidyl serine and the positive YOPRO-1 staining of the early apoptotic nucleus were also prevented by melatonin. A mechanistic study at the mitochondrial level related to the early protection provided by melatonin revealed that the indole molecule significantly reduced mitochondrial reactive oxygen species (ROS) formation induced by H2O2 stress. Melatonin also prevented mitochondrial ROS generation caused by other organic hydroperoxides including tert-butyl hydroperoxide and cumene hydroperoxide. This antioxidative effect of melatonin is more potent than that of vitamin E. Via its ability to reduce mitochondrial ROS generation, melatonin prevented H2O2-induced mitochondrial calcium overload, mitochondrial membrane potential depolarization, and the opening of the mitochondrial permeability transition (MPT) pore. As a result, melatonin blocked MPT-dependent cytochrome c release, the downstream activation of caspase 3, the condensation and karyorrhexis of the nucleus and apoptotic fragmentation of nuclear DNA. Thus, the powerful mitochondrial protection provided by melatonin reinforces its therapeutic potential to combat a variety of oxidative stress-induced mitochondrial dysfunctions as well as mitochondria-mediated apoptosis in various diseases.
J Pineal Res 2004 Aug
PMID:Visualization of the antioxidative effects of melatonin at the mitochondrial level during oxidative stress-induced apoptosis of rat brain astrocytes. 1523 Aug 69

Compelling evidence indicates that excessive K+ efflux and intracellular K+ depletion are key early steps in apoptosis. Previously, we reported that apoptosis of cerebellar granular neurons induced by incubation under low K+ (5 mM) conditions was associated with an increase in delayed rectifier outward K+ current (IK) amplitude and caspase-3 activity. Moreover, the melatonin receptor antagonist 4P-PDOT abrogated the effects of 2-iodomelatonin on IK augmentation, caspase-3 activity and apoptosis. Here, we show that incubation under low K+/serum-free conditions for 6 hr led to a dramatic increase in the A-type transient outward K+ current (IA) (a 27% increase; n=31); in addition, fluorescence staining showed that under these conditions, cell viability decreased by 30% compared with the control. Treatment with 2-iodomelatonin inhibited the IA amplitude recorded from control and apoptotic cells in a concentration-dependent manner and modified the IA channel activation kinetics of cells under control conditions. Moreover, 2-iodomelatonin increased the viability of cell undergoing apoptosis. Interestingly, 4P-PDOT did not abrogate the effect of 2-iodomelatonin on IA augmentation under these conditions; in the presence of 4P-PDOT (100 microm), 2-iodomelatonin reduced the average IA by 41+/-4%, which was similar to the effect of 2-iodomelatonin alone. These results suggest that the neuroprotective effects of 2-idomelatonin are not only because of its antioxidant or receptor-activating properties, but rather that 2-iodomelatonin may inhibit IA channels by acting as a channel blocker.
J Pineal Res 2005 Jan
PMID:2-iodomelatonin prevents apoptosis of cerebellar granule neurons via inhibition of A-type transient outward K+ currents. 1561 37

During oxidative stress, cell apoptosis is promoted through the mitochondrial death pathway. Increased reactive oxygen species (ROS) are linked to excess cell loss and mediate the induction of apoptosis in various cell types. However, the role of ROS in the apoptotic pathway has not been clearly established. The aims of this study were to investigate the biochemical and morphological responses of rat astrocytes to hydrogen peroxide-mediated cell death and to define the role that melatonin might play in the apoptotic cascade. Hydrogen peroxide (H2O2; 0.1-1.0 mM) significantly reduced cell viability. Astrocyte death was associated with enhanced ROS production in a dose-dependent manner, as measured by 2',7'-dichloro-fluorescein fluorescence. H2O2-induced cell death was found to be mediated through an apoptotic pathway as treated cells exhibited cell shrinkage, nuclear condensation and marked DNA fragmentation. H2O2 also triggered caspase-3 activation and Bax expression. The ability of different antioxidants to prevent H2O2-induced apoptosis was examined by pre-incubating rat astrocytes with N-acetylcysteine (10 mM), glutathione (0.5 mM) or melatonin (0.1 mM and 10 nM). Results showed that N-acetylcysteine and glutathion can protect astrocytes against ROS accumulation and caspase-3 activation, whereas 0.1 mM melatonin can inhibit H2O2-induced apoptosis by regulating Bax expression and by inhibiting caspase-3 activation. Antiapoptotic effect of 10 nM melatonin associated to inhibition of Bax expression, give rise to new therapeutic approaches.
J Pineal Res 2005 Mar
PMID:Melatonin prevents hydrogen peroxide-induced Bax expression in cultured rat astrocytes. 1568 62

Amifostine is a well-known cell protector and its actions involve free radical scavenging, which is also considered as a mechanism underlying the protective actions of melatonin, a secretory product of the pineal gland. In this work we compared the action of 14 mM amifostine and 50 microM melatonin on DNA damage and apoptosis induced by idarubicin in normal human lymphocytes, leukemic K562 cells and HeLa cancer cells. We employed the alkaline comet assay and pulse-field gel electrophoresis to estimate DNA damage. Apoptosis was evaluated by caspase 3 activity assay assisted by the comet assay to evaluate DNA fragmentation and DAPI staining for detection of morphological changes in chromatin. We found that idarubicin induced apoptosis in normal and cancer cells and its level was correlated with the extent of DNA strand breaks. Amifostine reduced apoptosis and DNA damage in normal cells, but it potentiated these effects in cancer cells in this in vitro study. Melatonin protected both normal and cancer cells against genotoxic treatment and apoptosis induced by idarubicin. We conclude that despite its recognized potential as an antioxidant, melatonin should be considered with caution when used in combination with cancer chemotherapy agents, especially in the case of leukemias.
J Pineal Res 2005 May
PMID:A comparison of the action of amifostine and melatonin on DNA-damaging effects and apoptosis induced by idarubicin in normal and cancer cells. 1581 2


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