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)

Apoptosis is the mode of photoreceptor cell death in inherited and induced retinal degeneration. However, the molecular mechanisms of photoreceptor cell death in human cases and animal models of retinal dystrophies remain undefined. Exposure of Balb/c mice to excessive levels of white light results in photoreceptor apoptosis. This study delineates the molecular events occurring during and subsequent to the induction of retinal degeneration by exposure to white light in Balb/c mice. We demonstrate an early increase in intracellular calcium levels during photoreceptor apoptosis, an event that is accompanied by significant superoxide generation and mitochondrial membrane depolarization. Furthermore, we show that inhibition of neuronal nitric-oxide synthase (nNOS) by 7-nitroindazole is sufficient to prevent retinal degeneration implicating a key role for neuronal nitric oxide (NO) in this model. We demonstrate that inhibition of guanylate cyclase, a downstream effector of NO, also prevents photoreceptor apoptosis demonstrating that guanylate cyclase too plays an essential role in this model. Finally, our results demonstrate that caspase-3, frequently considered to be one of the key executioners of apoptosis, is not activated during retinal degeneration. In summary, the data presented here demonstrate that light-induced photoreceptor apoptosis in vivo is mediated by the activation of nNOS and guanylate cyclase and is caspase-3-independent.
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PMID:Light-induced photoreceptor apoptosis in vivo requires neuronal nitric-oxide synthase and guanylate cyclase activity and is caspase-3-independent. 1127 85

The mechanism by which nitric oxide (NO) protects from apoptosis is a matter of debate. We have shown previously that phosphorylation of tyrosine residues participates in the protection from apoptosis in insulin-producing RINm5F cells (Inorg. Chem. Commun. 3 (2000) 32). Since NO has been reported to activate the tyrosine kinase c-Src and this kinase is involved in the activation of protein kinase G (PKG) in some cell systems, we aimed at studying the contribution of c-Src and PKG systems in anti-apoptotic actions of NO in serum-deprived RINm5F cells. Here we report that exposure of serum-deprived cells to 10 microM DETA/NO results in protection from degradation of the anti-apoptotic protein Bcl-2, together with a reduction of cytochrome c release from mitochondria and caspase-3 inhibition. Studies with the inhibitors ODQ and KT-5823 revealed that these actions are dependent on both activation of guanylate cyclase and PKG. DETA/NO was also able to induce autophosphorylation and activation c-Src protein both in vivo and in vitro and active c-Src was able to induce tyrosine phosphorylation of Bcl-2 in vitro. The c-Src kinase inhibitor PP1 abrogated the actions of DETA/NO on cGMP formation, PKG activation, caspase activation, cytochrome c release from mitochondria, and Bcl-2 phosphorylation and degradation in serum-deprived cells. We thus propose that activation of c-Src is an early step in the chain of events that signal cGMP-dependent anti-apoptotic actions of NO in mitocohondria.
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PMID:Evidence for involvement of c-Src in the anti-apoptotic action of nitric oxide in serum-deprived RINm5F cells. 1158 16

Apoptotic death results from disrupting the balance between anti-apoptotic and pro-apoptotic cellular signals. The inter- and intracellular messenger nitric oxide is known to mediate either death or survival of neurones. In the present work, cerebellar granule cells were used as a model to assess the survival role of nitric oxide and to find novel signal transduction pathways related to this role. It is reported that sustained inhibition of nitric oxide production induces apoptosis in differentiated cerebellar granule neurones and that compounds that slowly release nitric oxide significantly revert this effect. Neuronal death was also reverted by a caspase-3-like inhibitor and by a cyclic GMP analogue, thus suggesting that nitric oxide-induced activation of guanylate cyclase is essential for the survival of these neurones. We also report that the Akt/GSK-3 kinase system is a transduction pathway related to the survival action of nitric oxide, as apoptosis caused by nitric oxide deprivation is accompanied by down-regulation of this, but not of other, kinase systems. Conversely, treatments able to rescue neurones from apoptosis also counteracted this down-regulation. Furthermore, in transfection experiments, overexpression of the Akt gene significantly decreased nitric oxide deprivation-related apoptosis. These results are the first evidence for a mechanism where endogenous nitric oxide promotes neuronal survival via Akt/GSK-3 pathway.
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PMID:Akt pathway mediates a cGMP-dependent survival role of nitric oxide in cerebellar granule neurones. 1206 69

We examined the effect of 3-ethyl-3-(ethylaminoethyl)-1-hydroxy-2-oxo-1-triazene (NOC12), a nitric oxide (NO) donor, on apoptosis in cultured astrocytes. Reperfusion after hydrogen peroxide (H2O2) exposure caused a decrease in cell viability, loss of mitochondrial membrane potential, caspase-3 activation, DNA ladder formation, and nuclear condensation. NOC12 at 10-100 microM significantly attenuated these apoptotic changes, while the NO donor at 1 mM caused cell injury and exacerbated the H202-induced cell injury. NOC12 increased intracellular cGMP levels in a dose dependent manner with the maximal effect at 100 microM. The protective effect of NOC12 was mimicked by the NO-independent guanylate cyclase activator 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole, and was attenuated by the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) and the cGMP-dependent protein kinase inhibitor KT5823. ODQ and KT5823 did not block but rather exacerbated the cytotoxic effect of NOC12 at 1 mM. These findings demonstrate that lower concentrations of NOC12 inhibit the H2O2-induced apoptosis of astrocytes in a cGMP-dependent way, but higher concentrations of NOC12 show a toxic effect on astrocytes in a cGMP-independent way.
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PMID:The nitric oxide donor NOC12 protects cultured astrocytes against apoptosis via a cGMP-dependent mechanism. 1208 44

Human neuroblastoma cells, SH-SY5Y, contain relatively low levels of thioredoxin (Trx); thus, they serve favorably as a model for studying oxidative stress-induced apoptosis (Andoh, T., Chock, P. B., and Chiueh, C. C. (2001) J. Biol. Chem. 277, 9655-9660). When these neurotrophic cells were subjected to nonlethal 2-h serum deprivation, their neuronal nitric oxide synthase and Trx were up-regulated, and the cells became more tolerant of oxidative stress, indicating that NO may protect cells from serum deprivation-induced apoptosis. Here, the mechanism by which NO exerts its protective effects was investigated. Our results reveal that in SH-SY5Y cells, NO inhibits apoptosis through its ability to activate guanylate cyclase, which in turn activates the cGMP-dependent protein kinase (PKG). The activated PKG is required to protect cells from lipid peroxidation and apoptosis, to inhibit caspase-9 and caspase-3 activation, and to elevate the levels of Trx peroxidase-1 and Trx, which subsequently induces the expression of Bcl-2. Furthermore, active PKG promotes the elevation of c-Jun, phosphorylated MAPK/ERK1/2, and c-Myc, consistent with the notion that PKG enhances the expression of Trx through its c-Myc-, AP-1-, and PEA3-binding motifs. Elevation of Trx and Trx peroxidase-1 and Mn(II)-superoxide dismutase would reduce H(2)O(2) and O(2)(), respectively. Thus, the cytoprotective effect of NO in SH-SY5Y cells appears to proceed via the PKG-mediated pathway, and S-nitrosylation of caspases plays a minimal role.
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PMID:Cyclic GMP-dependent protein kinase regulates the expression of thioredoxin and thioredoxin peroxidase-1 during hormesis in response to oxidative stress-induced apoptosis. 1241 92

Vascular smooth muscle cells (SMCs) generate carbon monoxide (CO) from the degradation of heme by the enzyme heme oxygenase. Because recent studies indicate that CO influences the properties of vascular SMCs, we examined whether this diatomic gas regulates apoptosis in vascular SMCs. Treatment of cultured rat aortic SMCs with a cytokine cocktail consisting of interleukin-1beta (5 ng/ml), tumor necrosis factor-alpha (20 ng/ml), and interferon-gamma (200 U/ml) for 48 hr stimulated apoptosis, as demonstrated by DNA laddering, caspase-3 activation, and annexin V staining. However, the exogenous addition of CO (200 ppm) completely blocked cytokine-mediated apoptosis. The antiapoptotic action of CO was partially reversed by the soluble guanylate cyclase inhibitor, H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (10 microM). In contrast, the p38 mitogen-activated protein kinase inhibitor, SB203580 (10 microM), had no effect on SMC apoptosis. These findings indicate that CO is a potent inhibitor of vascular SMC apoptosis and that it blocks apoptosis, in part, by activating the cGMP signaling pathway. The ability of CO to inhibit vascular SMC apoptosis may play a critical role in attenuating lesion formation at sites of arterial damage.
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PMID:Antiapoptotic action of carbon monoxide on cultured vascular smooth muscle cells. 1270 89

1. We investigated the cytoprotective effect of low-dose nitric oxide (NO) on NO-induced cell death in mouse macrophage-like cell line RAW264. 2. Sodium nitroprusside (SNP), an NO donor, at a high concentration (4 mM) released cytochrome c from mitochondria and induced death in RAW264 cells. Acetyl-L-aspartyl-L-glutamyl-L-valyl-L-aspart-1-al (Ac-DEVD-CHO, 100-200 microM), a caspase-3 inhibitor, attenuated the SNP-induced cell death in a concentration-dependent manner. 3. Pretreatment with 100 microM SNP for 24 h, which had no effect on cell viability, attenuated the cell death and reduced cytochrome c release from mitochondria to the cytosol induced by 4 mM SNP. 4. LY83583 (1-3 microM) and 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ, 30-100 microM), soluble guanylate cyclase inhibitors, negated the protective effect of the 100 microM SNP pretreatment. 5. Pretreatment with 1 mM dibutylyl guanosine-3',5'-cyclic monophosphate (DBcGMP), a cell-permeable guanosine-3',5'-cyclic monophosphate (cGMP) analogue, for 24 h inhibited both cytochrome c release and cell death induced by SNP. 6. Protein kinase G inhibitor KT5823 (10 microM) significantly reduced the cytoprotective effects of low-dose SNP and DBcGMP. 7. These results indicate that low-dose NO protects RAW264 cells from NO-induced apoptosis through cGMP production and activation of protein kinase G.
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PMID:Nitric oxide at a low concentration protects murine macrophage RAW264 cells against nitric oxide-induced death via cGMP signaling pathway. 1274 20

Nephrotoxicity is one of the main side effects caused by cisplatin (CP), a widely used antineoplastic agent. Here, we examined the effect of a novel water-soluble carbon monoxide-releasing molecule (CORM-3) on CP-mediated cytotoxicity in renal epithelial cells and explored the potential therapeutic benefits of carbon monoxide in CP-induced nephrotoxicity in vivo. Exposure of LLC-PK(1) cells to CP (50 microM) caused significant apoptosis as evidenced by caspase-3 activation and an increased number of floating cells. Treatment with CORM-3 (1-50 microM) resulted in a remarkable and concentration-dependent decrease in CP-induced caspase-3 activity and cell detachment. This effect involved activation of the cGMP pathway as 1H-oxadiazole [4, 3-a] quinoxaline-1-ore (ODQ), a guanylate cyclase inhibitor, completely abolished the protection elicited by CORM-3. Using a rat model of CP-induced renal failure, we found that treatment with CP (7.5 mg/kg) caused a significant elevation in plasma urea (6.6-fold) and creatinine (3.1-fold) levels, which was accompanied by severe morphological changes and marked apoptosis in tubules at the corticomedullary junction. A daily administration of CORM-3 (10 mg/kg ip), starting 1 day before CP treatment and continuing for 3 days thereafter, resulted in amelioration of renal function as shown by reduction of urea and creatinine levels to basal values, a decreased number of apoptotic tubular cells, and an improved histological profile. A negative control (iCORM-3) that is incapable of liberating CO failed to prevent renal dysfunction mediated by CP, indicating that CO is directly involved in renoprotection. Our data demonstrate that CORM-3 can be used as an effective therapeutic adjuvant in the treatment of CP-induced nephrotoxicity.
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PMID:Protection against cisplatin-induced nephrotoxicity by a carbon monoxide-releasing molecule. 1652 24

Nicorandil has been shown to inhibit myocyte apoptosis by opening of mitochondrial ATP-sensitive potassium (mitoK(ATP)) channels and nitrate-like effect against oxidative stress. However, the detailed mechanism of nicorandil-mediated cardioprotection under hypoxic conditions remains to be largely unknown. The present study examined whether nicorandil can inhibit apoptosis via regulation of Bcl-2 family proteins in hypoxic myocytes. Neonatal rat cardiac myocytes were exposed to hypoxia for 7 hours. Hypoxia-induced myocyte apoptosis (13.9+/-0.9%) under glucose-rich conditions. Myocyte apoptosis was accompanied by loss of mitochondrial membrane potential (Deltapsi(m)), cytochrome c release from mitochondria into cytosol, and activation of caspase-3. Hypoxia also significantly increased Bax and decreased Bcl-2 mRNA and protein expression, thereby increasing Bax/Bcl-2 ratio. Nicorandil 100 micromol/l significantly decreased the percentage of apoptotic myocytes (7.2+/-0.5%) by inhibiting loss of Deltapsi(m) and translocation of cytochrome c. These effects of nicorandil were partially but significantly inhibited by cotreatment of either 500 micromol/l 5-hydroxydecanoate, a selective mitoK(ATP) channel antagonist, or 10 micromol/l 1H-[1,2,4]oxidazolo[4,3-a]quinoxalin-1-one (ODQ), an inhibitor of soluble guanylate cyclase. Moreover, nicorandil significantly inhibited the hypoxia-induced changes in Bax and Bcl-2 expression, and concomitant increased Bax and decreased Bcl-2 immunoreactivity in mitochondria. These effects of nicorandil in Bax and Bcl-2 expression were significantly blunted by cotreatment of ODQ and 5-HD, respectively. Cotreatment of KT5823, an inhibitor of protein kinase G, significantly blocked the effect of nicorandil on Bax expression and 8-bromo-cyclic guanosine 3',5' monophosphate (8-bromo-cGMP), a cGMP analog, mimicked the effect of nicorandil on Bax expression. The present study demonstrates that nicorandil regulates Bcl-2 family proteins via opening of mitoK(ATP) channels and nitric oxide-cGMP signaling and inhibits hypoxia-induced mitochondrial death pathway.
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PMID:Nicorandil regulates Bcl-2 family proteins and protects cardiac myocytes against hypoxia-induced apoptosis. 1652 5

The clinical utility of anthracycline anticancer agents, especially doxorubicin, is limited by a progressive toxic cardiomyopathy linked to mitochondrial damage and cardiomyocyte apoptosis. Here we demonstrate that the post-doxorubicin mouse heart fails to upregulate the nuclear program for mitochondrial biogenesis and its associated intrinsic antiapoptosis proteins, leading to severe mitochondrial DNA (mtDNA) depletion, sarcomere destruction, apoptosis, necrosis, and excessive wall stress and fibrosis. Furthermore, we exploited recent evidence that mitochondrial biogenesis is regulated by the CO/heme oxygenase (CO/HO) system to ameliorate doxorubicin cardiomyopathy in mice. We found that the myocardial pathology was averted by periodic CO inhalation, which restored mitochondrial biogenesis and circumvented intrinsic apoptosis through caspase-3 and apoptosis-inducing factor. Moreover, CO simultaneously reversed doxorubicin-induced loss of DNA binding by GATA-4 and restored critical sarcomeric proteins. In isolated rat cardiac cells, HO-1 enzyme overexpression prevented doxorubicin-induced mtDNA depletion and apoptosis via activation of Akt1/PKB and guanylate cyclase, while HO-1 gene silencing exacerbated doxorubicin-induced mtDNA depletion and apoptosis. Thus doxorubicin disrupts cardiac mitochondrial biogenesis, which promotes intrinsic apoptosis, while CO/HO promotes mitochondrial biogenesis and opposes apoptosis, forestalling fibrosis and cardiomyopathy. These findings imply that the therapeutic index of anthracycline cancer chemotherapeutics can be improved by the protection of cardiac mitochondrial biogenesis.
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PMID:The CO/HO system reverses inhibition of mitochondrial biogenesis and prevents murine doxorubicin cardiomyopathy. 1803 88


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