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)

We previously demonstrated that ginsenoside Rg(3) (Rg(3)), one of the active ingredients in Panax ginseng, attenuates NMDA receptor-mediated currents and NMDA-induced neurotoxicity (Kim, S., Kim, T., Ahn, K., Park, W.K., Nah, S.Y., Rhim, H., 2004. Ginsenoside Rg(3) antagonizes NMDA receptors through a glycine modulatory site in rat cultured hippocampal neurons. Biochem. Biophys. Res. Commun. 323, 416-424). Accumulating evidence suggests that homocysteine (HC), a metabolite of methionine, exerts its excitotoxicity through NMDA receptor activation. In the present study, we examined the neuroprotective effects of Rg(3) on HC-induced hippocampal excitotoxicity in vitro and in vivo. Our in vitro studies using rat cultured hippocampal neurons revealed that Rg(3) treatment significantly and dose-dependently inhibited HC-induced hippocampal cell death, with an EC(50) value of 28.7+/-7.5 muM. Rg(3) treatment not only significantly reduced HC-induced DNA damage, but also dose-dependently attenuated HC-induced caspase-3 activity in vitro. Our in vivo studies revealed that intracerebroventricular (i.c.v.) pre-administration of Rg(3) significantly and dose-dependently reduced i.c.v. HC-induced hippocampal damage in rats. To examine the mechanisms underlying the in vitro and in vivo neuroprotective effects of Rg(3) against HC-induced hippocampal excitotoxicity, we examined the effect of Rg(3) on HC-induced intracellular Ca(2+) elevations in cultured hippocampal cells and found that Rg(3) treatment dose-dependently inhibited HC-induced intracellular Ca(2+) elevation, with an IC(50) value of 41.5+/-17.5 muM. In addition, Rg(3) treatment dose-dependently inhibited HC-induced currents in Xenopus oocytes expressing the NMDA receptor, with an IC(50) of 47.3+/-14.2 muM. These results collectively indicate that Rg(3)-induced neuroprotection against HC in rat hippocampus might be achieved via inhibition of HC-mediated NMDA receptor activation.
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PMID:Neuroprotective effects of ginsenoside Rg3 against homocysteine-induced excitotoxicity in rat hippocampus. 1723 31

Homocysteine (HCY) is toxic on blood vessels, but a potential direct toxicity of HCY on the heart is unknown. We addressed this issue by exposing H9C2 cardiomyocytes to HCY (0.1-5 mM) for up to 6h. At these concentrations, HCY reduced cell viability, induced necrosis and apoptosis and triggered the cleavage of caspase-3 and poly(ADP-ribose) polymerase (PARP). This was associated with the intracellular generation of the potent oxidant peroxynitrite. Removing peroxynitrite by the decomposition catalyst FeTPPS considerably reduced LDH release, DNA fragmentation, cleavage of caspase-3 and PARP, and restored normal cell morphology. In additional experiments performed in primary rat ventricular cardiomyocytes, HCY (1 mM, 6h) activated the phosphorylation of the MAP kinases ERK and JNK, two essential stress signaling kinases regulating myocardial apoptosis, hypertrophy and remodeling. These results provide the first demonstration that HCY kills cardiomyocytes through the generation of peroxynitrite and can activate key signaling cascades in the myocardium.
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PMID:Homocysteine induces cell death in H9C2 cardiomyocytes through the generation of peroxynitrite. 1754 63

The effects of exogenous ethanol (EtOH) and/or glycine on chick (Gallus gallus) embryo viability, brain apoptosis (caspase-3 activities), and the endogenous levels of brain homocysteine (HoCys), S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), and SAM/SAH were studied. Embryonic EtOH exposure caused decreased embryo viability as measured by EtOH-induced reductions in % living embryos at theoretical stage 37, EtOH-induced reductions in embryo masses, and EtOH-induced reductions in brain caspase-3 (Casp-3) activities. Exogenous glycine failed to attenuate EtOH-induced decreased embryo viability and EtOH-induced increased brain Casp-3 activities. Embryonic EtOH exposure caused elevated levels of endogenous HoCys, decreased levels of SAM, increased levels of SAH, and decreased SAM/SAH ratios in embryonic chick brains. While exogenous glycine failed to attenuate EtOH-induced increased HoCys levels, exogenous glycine attenuated EtOH-induced decreased levels of SAM, increased levels of SAH, and decreased SAM/SAH levels in embryonic chick brains.
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PMID:Ethanol-induced increased endogenous homocysteine levels and decreased ratios of SAM/SAH are only partially attenuated by exogenous glycine in developing chick brains. 1796 82

Clinical studies have raised the possibility that elevated plasma levels of homocysteine increase the risk of atherosclerosis, stroke and possibly neurodegenerative diseases such as Alzheimer's disease (AD); however, the direct impact of homocysteine on neuron cells and the mechanism by which it could induce neurodegeneration have yet to be clearly demonstrated. Here, we investigated the effect of homocysteine on endoplasmic reticulum (ER) stress, the suggested mechanism of neurotoxicity, in human neuroblastoma SH-SY5Y cells. The effect of homocysteine on amyloid-beta (Abeta)-induced neurotoxicity and the protective activity of folate were also investigated. Homocysteine led to increased expressions of the binding protein (BiP) and the spliced form of X-box-protein (XBP)-1 mRNAs, suggesting activation of the unfolded-protein response and an increase in apoptosis. When cells were cotreated with homocysteine and Abeta, caspase-3 activity was significantly increased, and expressions of BiP and the spliced form of XBP-1 mRNAs were significantly induced. The neurotoxicity of homocysteine was attenuated by the treatment of cells with folate, as determined by caspase-3 activity and apoptotic body staining. These findings indicate that homocysteine induces ER stress and, ultimately, apoptosis and sensitizes neurons to amyloid toxicity via the synergistic induction of ER stress. Furthermore, a neuroprotective effect of folate against homocysteine-induced toxicity was also observed. Therefore, the findings of our study suggest that ER stress-induced homocysteine toxicity may play an important physiological role in enhancing the pathogenesis of Abeta-induced neuronal degeneration.
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PMID:Synergistic induction of ER stress by homocysteine and beta-amyloid in SH-SY5Y cells. 1843 May 56

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease caused by selective degeneration of motor neurons. Mutations in copper/zinc superoxide dismutase (SOD1) account for 20% cases of familial ALS (fALS), but the underlying pathogenetic mechanisms are largely unknown. Using SOD1(G93A) mice model of ALS, we demonstrated that mutation in SOD1 caused a significant increase in the level of plasma homocysteine (Hcy). To investigate whether Hcy-lowering therapy is beneficial to this disease, we applied folic acid (FA) and vitamin B12 which are important factors involved in the Hcy metabolism to assess the neuroprotective effect of FA and B12 in the SOD1(G93A) mice. Our results showed FA or FA+B12 treatment significantly delayed the disease onset and prolonged the lifespan, accompanied by the significant reduction of motor neuron loss. Furthermore, we found that FA or FA+B12 treatment significantly attenuated the plasma Hcy level, suppressed the activation of microglia and astrocytes, and inhibited the expression of inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-alpha) in spinal cord. Moreover, FA or FA+B12 treatment decreased the levels of cleaved caspase-3 and poly(ADP-ribose)polymerase (PARP) but up-regulated the level of anti-apoptotic protein Bcl-2. However, B12 treatment alone did not show any significant benefit to this disease. These results provide evidence to demonstrate that elevated Hcy is involved in the pathogenesis of fALS and FA therapy may have therapeutic potential for the treatment of the disease.
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PMID:Folic acid protects motor neurons against the increased homocysteine, inflammation and apoptosis in SOD1 G93A transgenic mice. 1843 68

Cobalamin-dependent methionine synthase, with a cofactor of vitamin B12, catalyzes the reaction of 5-methyltetrahydrofolate and homocysteine to form methionine and tetrahydrofolate, which takes a core position in folate cycle, one-carbon-unit transfer, and sulfur amino acid pathways. The 'methyl folate trap' hypothesis suggests that methionine synthase is a potential target for anticancer drug development. ZL031 and ZL033 are 5-methyltetrahydrofolate-like compounds that have been newly synthesized as potential inhibitors of the enzyme. To identify the effect of these two compounds on methionine synthase activity, a spectrophotometric assay was used and the results proved that ZL031 and ZL033 inactivated methionine synthase in HL-60 cells with an IC50 dose of 10.0 and 1.4 mumol/l, respectively. Moreover, obvious inhibitory effect on proliferation of HL-60 cells was observed, leading to our further investigation of the underlying anticancer mechanism. Under the circumstances of methionine synthase deficiency and subsequent folate depletion, cell cycle was arrested in G1/S phase and apoptosis was also observed. Analysis of cell cycle regulatory proteins demonstrated that cyclin E and cyclin-dependent kinase 2 were both increased. Furthermore, reduction of caspase-3, poly (ADP-ribose) polymerase, caspase-8, and caspase-9 protein levels were observed. In all the biological experiments we have performed, ZL033 has shown a better efficacy compared with ZL031. These results suggest that ZL031 and ZL033, as novel methionine synthase inhibitors, caused G1/S phase delay and apoptosis and eventually inhibit the proliferation of HL-60 cells in vitro. ZL033, with a carboxylic acid substituent, might have a better potential for drug development than ZL031 with an ester substituent.
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PMID:Two newly synthesized 5-methyltetrahydrofolate-like compounds inhibit methionine synthase activity accompanied by cell cycle arrest in G1/S phase and apoptosis in vitro. 1859 11

Homocysteine (Hcy) is a risk factor for vascular dysfunction. High levels of Hcy may result in vascular injury accelerating atherosclerosis leading to ischemia. After ischemia, endothelial progenitor cells (EPCs) migrate from bone marrow to repair damaged sites either through direct incorporation of EPCs or by repopulating mature endothelial cells. This study looks into the relationship between increased Hcy in patients with cerebrovascular disease (CVD) and EPCs. Some patients with hyperhomocysteinemia were treated with B vitamins to evaluate if the treatment reverses the elevated Hcy and its impact on their EPC levels. EPCs were treated with Hcy to determine the in vitro effects of Hcy. Our clinical findings show that elevated Hcy levels have an inverse relationship with EPC levels and B vitamin intervention can reverse this effect. Our in vitro work shows that Hcy-mediated EPC toxicity is due to apoptosis involving caspase-8, cytochrome c release, and caspase-3 activation. Vitamin B(6), and B(9) significantly impair Hcy-mediated EPC caspase-3 activation in vitro. Our clinical and in vitro data together indicate that increased Hcy results in a decrease in EPC numbers. This decrease in EPC by Hcy may be occurring through increased apoptosis and B vitamins (B(6), B(9)) intervention can attenuate such effects.
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PMID:Homocysteine reduces endothelial progenitor cells in stroke patients through apoptosis. 1876 98

Hepatic steatosis is a clinical feature observed in severe hyperhomocysteinemic patients. In mice, cystathionine beta synthase (CBS) deficiency, the most common cause of severe hyperhomocysteinemia, is also associated with steatosis, fibrosis and inflammation. Proinflammatory cytokines usually induce apoptosis. However, hyperhomocysteinemia does not increase apoptosis in liver of CBS-deficient mice compared to wild type mice. The aim of the study was to analyze the activation state of the NF-kappaB pathway in liver of CBS-deficient mice and to investigate its possible involvement in anti-apoptotic signals. We analyzed the level of I kappaB alpha in liver of CBS-deficient mice. A co-culture of primary hepatocytes and Kupffer cells was also used in order to investigate how I kappaB alpha degradation occurs in response to homocysteine. We found lower I kappaB alpha level not only in liver of CBS-deficient mice but also in hepatocyte/Kupffer cell co-culture. The homocysteine-mediated I kappaB alpha enhanced proteolysis occurred via calcium-dependent calpains, which was supported by an increased level of calpain activity and a reduced expression of calpastatin in liver of CBS-deficient mice. Intraperitoneal administration of the inhibitor PDTC normalized the expression of two genes induced by NF-kappaB activation, heme oxygenase-1 and cellular inhibitor of apoptosis 2. Moreover, PDTC administration induced an increase of caspase-3 activity in liver of CBS-deficient mice. Our results suggest that hyperhomocysteinemia induces calpain-mediated I kappaB alpha degradation which is responsible for anti-apoptotic signals in liver.
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PMID:Calpain activation is required for homocysteine-mediated hepatic degradation of inhibitor I kappa B alpha. 1929 76

The present study addresses how homocysteine (Hcy) induces endothelial apoptosis and how simvastatin antagonizes these pro-apoptotic effects of Hcy.Human umbilical vein endothelial cells (HUVECs) were treated with Hcy for 24 h, in the presence or absence of simvastatin. Cell apoptosis was evaluated by Annexin V staining and flow cytometry, as well as transferase-mediated dUTP-biotin nick end labeling (TUNEL). The mRNA and protein levels of caspase-3, cellular inhibitor of apoptosis (cIAP)-1 and -2 were analyzed by real-time polymerase chain reaction (RT-PCR) and western blotting, respectively.Treatment with both low (0.05 mmol l(-1)) and high (0.3 mmol l(-1)) concentrations of Hcy induced apoptosis in HUVECs which was accompanied by an increased level of caspase-3 expression and activation, together with decreased cIAP-1 and cIAP-2 levels. Conversely, simvastatin upregulated c-IAP1 and c-IAP2 expression, while attenuating Hcy-induced apoptosis and caspase-3 activation. Hcy may induce HUVEC apoptosis through a pathway involving caspase-3. This induction can be partially antagonized by simvastatin, possibly through upregulation of cIAP-1 and cIAP-2.
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PMID:Simvastatin suppresses homocysteine-induced apoptosis in endothelial cells: roles of caspase-3, cIAP-1 and cIAP-2. 1934 37

Cellular events for neural progenitor cells, such as proliferation and differentiation, are regulated by multiple intrinsic and extrinsic cell signals. Folate plays a central role in central nervous system development, so folate, as an extrinsic signal, may affect neural stem cell (NSC) proliferation and differentiation. In the present study, we investigated the effects of folate deficiency on the cell proliferation, cell apoptosis and homocysteine concentrations in NSCs. NSCs were isolated from fetal rats and identified as NSCs by their expression of immunoreactive nestin. Cell proliferation was quantitated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Apoptotic cells were detected and confirmed by flow cytometric analysis. We measured homocysteine concentrations in NSCs by high performance liquid chromatography and detected the expression of caspase-3 by western blot method. Folate deficiency not only decreased cell proliferation, but also increased the apoptotic rate of NSCs as demonstrated by the increased expression of early apoptotic markers such as caspase-3, compared to control group (p<0.05). Furthermore, There was a statistically significant increase in homocysteine concentration during folate deficiency in NSCs (p<0.05). These data suggest that folate affects the cell proliferation, apoptosis and homocysteine generation in NSC cells.
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PMID:Folate deficiency induces neural stem cell apoptosis by increasing homocysteine in vitro. 1959 Jul 2


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