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)

It is unclear what mechanisms lead to the degeneration of basal forebrain cholinergic neurons in Alzheimer's or other human brain diseases. Some brain cholinergic neurons express neuronal nitric oxide (NO) synthase (nNOS), which produces a free radical that has been implicated in some forms of neurodegeneration. We investigated nNOS expression and NO toxicity in SN56 cells, a clonal cholinergic model derived from the medial septum of the mouse basal forebrain. We show here that, in addition to expressing choline acetyltransferase (ChAT), SN56 cells express nNOS. Treatment of SN56 cells with retinoic acid (RA; 1 microM) for 48 h increased ChAT mRNA (+126%), protein (+88%), and activity (+215%) and increased nNOS mRNA (+98%), protein (+400%), and activity (+15%). After RA treatment, SN56 cells became vulnerable to NO excess generated with S-nitro-N-acetyl-DL-penicillamine (SNAP) and exhibited increased nuclear DNA fragmentation that was blocked with a caspase-3 inhibitor. Treatment with dexamethasone, which largely blocked the RA-mediated increase in nNOS expression, or inhibition of nNOS activity with methylthiocitrulline strongly potentiated the apoptotic response to SNAP in RA-treated SN56 cells. Caspase-3 activity was reduced when SNAP was incubated with cells or cell lysates, suggesting that NO can directly inhibit the protease. Thus, whereas RA treatment converts SN56 cells to a proapoptotic state sensitive to NO excess, endogenously produced NO appears to be anti-apoptotic, possibly by tonically inhibiting caspase-3.
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PMID:Retinoic acid-mediated enhancement of the cholinergic/neuronal nitric oxide synthase phenotype of the medial septal SN56 clone: establishment of a nitric oxide-sensitive proapoptotic state. 1082 Feb 2

Preconditioning stress induced by a transient ischemia may increase brain tolerance to oxidative stress, and the underlying neuroprotective mechanisms are not well understood. In a series of experiments, we found that endogenous nitric oxide (NO), S-nitrosoglutathione (GSNO), and antioxidants blocked serum deprivation-induced oxidative stress and apoptosis in human neuroblastoma cells. Similar to nuclear redox factor-1 (Ref-1), mRNA of human neuronal nitric oxide synthase (hNOS1) was maximally up-regulated within 2 h after oxidative stress and down-regulated by NO/GSNO and hydroxyl radical (OH) scavenger. A brief preconditioning stress induced by serum deprivation for 2 h caused a delayed increase in the expression of hNOS1 protein and the associated formation of NO and cGMP, which in turn decreased OH generation and stress-related cell death. In addition to inhibiting caspase-3 through a dithiothreitol-sensitive S-nitrosylation process, preconditioning stress concomitantly up-regulated the expression of the anti-apoptotic bcl-2 protein and down-regulated the p66shc adaptor protein. This beneficial cytoprotective process of preconditioning stress is mediated by newly synthesized NO because it can be suppressed by the inhibition of hNOS1 and guanylyl cyclase. Therefore, the constitutive isoform of hNOS1 is dynamically redox-regulated to meet both functional and compensatory demands of NO for gene regulation, antioxidant defense, and tolerance to oxidative stress.
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PMID:Preconditioning regulation of bcl-2 and p66shc by human NOS1 enhances tolerance to oxidative stress. 1102 98

Cyclooxygenase 2 (COX-2) inhibits nerve growth factor (NGF) withdrawal apoptosis in differentiated PC12 cells. The inhibition of apoptosis by COX-2 was concomitant with prevention of caspase 3 activation. To understand how COX-2 prevents apoptosis, we used cDNA expression arrays to determine whether COX-2 regulates differential expression of apoptosis-related genes. The expression of dynein light chain (DLC) (also known as protein inhibitor of neuronal nitric oxide synthase [PIN]) was significantly stimulated in PC12 cells overexpressing COX-2. The COX-2-dependent stimulation of DLC expression was, at least in part, mediated by prostaglandin E(2). Overexpression of DLC also inhibited NGF withdrawal apoptosis in differentiated PC12 cells. Stimulation of DLC expression resulted in an increased association of DLC/PIN with neuronal nitric oxide synthase (nNOS), thereby reducing nNOS activity. Furthermore, nNOS expression and activity were significantly increased in differentiated PC12 cells after NGF withdrawal. This increased nNOS activity as well as increased nNOS dimer after NGF withdrawal were inhibited by COX-2 or DLC/PIN overexpression. An nNOS inhibitor or a membrane-permeable superoxide dismutase (SOD) mimetic protected differentiated PC12 cells from NGF withdrawal apoptosis. In contrast, NO donors induced apoptosis in differentiated PC12 cells and potentiated apoptosis induced by NGF withdrawal. The protective effects of COX-2 on apoptosis induced by NGF withdrawal were also overcome by NO donors. These findings suggest that COX-2 promotes cell survival by a mechanism linking increased expression of prosurvival genes coupled to inhibition of NO- and superoxide-mediated apoptosis.
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PMID:Cyclooxygenase 2 promotes cell survival by stimulation of dynein light chain expression and inhibition of neuronal nitric oxide synthase activity. 1104 52

Axotomised dorsal root ganglia (DRG) neurons show an increased expression of neuronal nitric oxide synthase (nNOS) compared with neurons from the intact ganglia. Increased nNOS expression resulted in synthesis of nitric oxide (NO) and the subsequent activation of cGMP in satellite glia cells surrounding the DRG neuron soma. In dissociated DRG we have demonstrated that the increase in nNOS expression is regulated by nerve growth factor and that the subsequent inhibition of NO production or cGMP synthesis precipitates apoptosis of neurons expressing nNOS and some non-nNOS neurons. Hence, NO or the NO-cGMP cascade appears to have a neuroprotective action in trophic factor-deprived DRG neurons. In the present study, using immunocytochemistry, we have investigated some of the factors associated with apoptosis that are activated when nNOS activity is blocked with NOS inhibitor in DRG neurons in vitro. Marked elevation of bax was observed within a few hours of NOS inhibition in nNOS containing neurons, whereas pretreatment of cultures with l-arginine completely abolished this effect in almost all nNOS neurons and 8-bromo-cGMP in some neurons. The apoptosis precipitated by NOS inhibition was also partially prevented by a number of caspase inhibitors; of those a caspase-9 blocker was the most effective. These observations further support the neuroprotective role of NO/NO-cGMP in stressed DRG neurons in an autocrine fashion that involves the suppression of bax, caspase-3 and -9 activation.
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PMID:Bax and caspases are inhibited by endogenous nitric oxide in dorsal root ganglion neurons in vitro. 1170 52

The aim of this study was to investigate the vagal motoneuronal degeneration after right vagotomy using in situ hybridization, RT-PCR, and immunohistochemistry methods. The morphology of the vagal motoneurons in dorsal motor nucleus of the vagus nerve (DMV) and nucleus of ambiguus (NA) after right vagotomy was examined by using Nissl staing and TUNEL. The expression of inducible nitric oxide synthase (iNOS), bcl-2, bax, and caspase-3 in DMV and NA of rats after right vagotomy was studied. Additionally, the involvement of the N-methyl-D-aspartate (NMDA) receptor-calcium-neuronal nitric oxide synthase (nNOS) pathway in the vagal motoneuronal degeneration was addressed by double-immunolabeling analysis of nNOS with NMDAR1 and calbindin D28K in right-vagotomized rats. The neurons in right DMV and NA displayed a darkly stained, shrunken morphology at 1 day and 5 days following right vagotomy as shown by Nissl staining. Quantitative analysis revealed that, at 1 day and 5 days following right vagotomy, the number of neurons in right DMV, but not NA, was significantly reduced in comparison with that of control rats. Occasional TUNEL-positive neurons were detected in right DMV of rat at 1 day after right vagotomy. The expression of iNOS protein and mRNA was absent in DMV and NA of control rats. However, the iNOS mRNA expression was induced bilaterally in DMV and NA at 1 day postoperation and continued to be up-regulated until 5 days after vagotomy as shown by in situ hybridization. Immunohistochemistry analysis also showed the increased expression of iNOS in bilateral DMV and NA of vagotomized rats. RT-PCR analysis revealed the enhanced bcl-2 and reduced bax mRNA levels and subsequent up-regulation of both bcl-2 and bax mRNA in right sides of the vagotomized brainstems at 1 day and 5 days postoperation, respectively. In situ hybridization analysis confirmed the up-regulation of bcl-2 and bax mRNA in right DMV and NA of the rats at 5 days following operation. Immunohistochemistry analysis showed up-regulated Bcl-2 immunoreactivity and undetectable changes in Bax immunoreactivity in DMV and NA of rats at 1 day after vagotomy, whereas enhancement of both Bcl-2 and Bax immunoreactivity was observed at 5 days postoperation. In addition, the caspase-3 mRNA level was elevated ipsilaterally in DMV and NA at 1 day and 5 days following right vagotomy. Double-immunofluorescence analysis showed complete colocalization of nNOS with NMDAR1 and with calbindin in ipsilateral DMV and NA at 10 days following right vagotomy. This study suggests that the signal pathway for NMDAR1-calcium-nNOS and the up-regulation of iNOS in DMV and NA may be involved in the vagal motor neurodgeneration after right vagotomy. Furthermore, our results imply that the apoptosis pathway mediated by Bcl-2, Bax, and caspase-3 may be activated in vagal motoneurons after right vagotomy.
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PMID:Molecular analysis of the vagal motoneuronal degeneration after right vagotomy. 1212 81

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

Clinical studies suggest that estrogen may improve cognition in Alzheimer's patients. Basic experiments demonstrate that 17beta-estradiol protects against neurodegeneration in both cell and animal models. In the present study, a human SH-SY5Y cell model was used to investigate molecular mechanisms underlying the receptor-mediated neuroprotection of physiological concentrations of 17beta-estradiol. 17beta-estradiol (<10 nM) concomitantly increased neuronal nitric oxide synthase (NOS1) expression and cell viability. 17beta-estradiol-induced neuroprotection was blocked by the receptor antagonist ICI 182,780, also prevented by inhibitors of NOS1 (7-nitroindazole), guanylyl cyclase (LY 83,583), and cGMP-dependent protein kinase (PKG) (Rp-8-pCPT-cGMPs). In addition to the expression of NOS1 and MnSOD, 17beta-estradiol increased the expression of the redox protein thioredoxin (Trx), which was blocked by the inhibition of either cGMP formation or PKG activity. The expression of heme oxygenase 2 and brain-derived neurotrophic factor was not altered. Estrogen receptor-enhanced cell viability against oxidative stress may be linked to Trx expression because the Trx reductase inhibitor, 5,5'-dithio-bis(2-nitrobenzoic acid) significantly reduced the cytoprotective effect of 17beta-estradiol. Furthermore, Trx (1 microM) inhibited lipid peroxidation, proapoptotic caspase-3, and cell death during oxidative stress caused by serum deprivation. We conclude that cGMP-dependent expression of Trx--the redox protein with potent antioxidative and antiapoptotic properties--may play a pivotal role in estrogen-induced neuroprotection.
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PMID:17beta-estradiol activates ICI 182,780-sensitive estrogen receptors and cyclic GMP-dependent thioredoxin expression for neuroprotection. 1262 28

Nitric oxide has been shown to play an important role in regulation of bone resorption. However, the role of endogenous nitric oxide on osteoclast activity remains still controversial. In this work, using RT-PCR amplification, we demonstrated that rabbit mature osteoclasts express mRNA encoding for neuronal nitric oxide synthase suggesting that this enzyme could be involved in basal nitric oxide production in these cells. Then we assessed the effect of carboxy-PTIO, a nitric oxide scavenger, on in vitro bone resorption and osteoclast survival. Carboxy-PTIO (10-100 microM) inhibited osteoclastic bone resorption in a dose dependent manner and induced osteoclast apoptosis by a mechanism involving caspase 3 activation. These results suggest that basal concentration of endogenous nitric oxide may be essential for normal bone resorption by supporting osteoclast survival. Because osteoclasts express N-methyl-d-aspartate-receptor (NMDA-R), we hypothesized that in osteoclasts NMDA-R may be involved in nitric oxide production as in neuronal cells. We confirmed that blockade of NMDA-R with specific non-competitive antagonists, MK801 and DEP, strongly inhibited bone resorption. As for carboxy-PTIO, we showed that blockade of NMDA-R by both antagonists induced osteoclast apoptosis in a dose dependent manner by a mechanism dependent on caspase 3 activation. Intracellular calcium concentration in osteoclasts decreased within minutes in the presence of both antagonists. Finally, MK801-induced osteoclast apoptosis was partially reversed in the presence of small amount of SNAP (100 nM), a nitric oxide donor, suggesting that the effect of NMDA-R on osteoclast apoptotic cell death could be due to a decrease in nitric oxide production. Taken together, our results are consistent with the hypothesis that NMDA-R on osteoclasts could have a similar function as those in neuronal cells, i.e., to allow a calcium influx, which in turn activates a constitutive neuronal nitric oxide synthase. Nitric oxide generated by this pathway may be essential for osteoclast survival and hence for normal bone resorption.
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PMID:Regulation of bone resorption and osteoclast survival by nitric oxide: possible involvement of NMDA-receptor. 1264 97

Hypoxia results in generation of nitric oxide (NO) free radicals, activation of caspase-3, and genomic DNA fragmentation. The present study tests the hypothesis that hypoxia-induced caspase-3 activation and DNA fragmentation are nitric oxide mediated. Studies were conducted in newborn piglets, divided into normoxic (n = 5), hypoxic (n = 5), and hypoxic-7-NINA (n = 6). Hypoxic-7-NINA group received the neuronal nitric oxide synthase inhibitor, 7-Nitroindazole (7-NINA). Caspase-3 activity was determined spectrofluorometrically using enzyme-specific substrates. Sections from the neocortex were stained with an antiserum recognizing active caspase-3. Purified DNA was separated by gel electrophoresis. Administration of 7-NINA resulted in decreased immunoreactivity of caspase-3 (mean LI: 20.2%) as compared to the untreated hypoxia group (mean LI: 57.5%) (P < 0.05). 7-NINA attenuated caspase-3 enzymatic activity as well in comparison to the untreated hypoxia group (P < 0.05). Furthermore, multiple low molecular weight bands corresponding to DNA fragments were present in the hypoxic but not in the normoxic or hypoxic-7-NINA groups. Inhibition of nNOS abates the hypoxia-induced increase in active caspase-3 immunoreactivity, as well as enzymatic activity in cortical neurons, and DNA fragmentation in brain homogenates. We conclude that the coordinate increase of capase-3 activity and fragmentation of nuclear DNA in the hypoxic newborn piglet brain are NO mediated.
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PMID:Hypoxia-induced caspase-3 activation and DNA fragmentation in cortical neurons of newborn piglets: role of nitric oxide. 1293 57

Erectile dysfunction (ED) is commonly experienced in men with diabetes mellitus. Vascular endothelial growth factor (VEGF) has been extensively documented for its pathogenic significance in different complications of diabetes. We hypothesized that expressions of VEGF, its receptors and its signaling pathway Akt may be drastically altered in diabetic penile tIssues and their alterations may modulate penile expression of the molecules that are believed to play a role in diabetic ED. Otsuka Long-Evans Fatty (OLETF) rats, a type II (non-insulin-dependent) diabetes mellitus, were used at the insulin-resistant stage of type II diabetes (20 weeks of age). We determined protein and mRNA expressions of VEGF, its receptors, Akt, nitric oxide synthase isoforms, and apoptosis-related molecules in the penis using immunohistochemistry, Western blotting, in situ hybridization, and real-time quantitative PCR analyses. The penile sections were also submitted to the Tdt-mediated dUTP nick end labeling assay for apoptosis. OLETF rats showed marked reductions in penile expression of VEGF, its two receptors and Akt. In OLETF rat penises, endothelial and neuronal nitric oxide synthase isoforms were expressed less abundantly. Furthermore, while anti-apoptotic markers, Bcl-2 and phosphorylated Bad, were down-regulated, pro-apoptotic markers, active caspase-3 and Bax, were up-regulated, resulting in the appearance of apoptotic cells in the penile tIssues of OLETF rats. The VEGF signaling system would work less well in diabetic penile tIssues as a result of the reduced expression, leading to diminished endothelial production of nitric oxide and apoptosis-related erectile tIssue damage. We propose that the abnormalities of the VEGF signaling system in the penis may play a role in the pathophysiology of diabetic ED.
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PMID:Diminished penile expression of vascular endothelial growth factor and its receptors at the insulin-resistant stage of a type II diabetic rat model: a possible cause for erectile dysfunction in diabetes. 1466 2


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