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)

Previous studies established that the populations of neurons that frequently degenerate in Alzheimer's disease exhibit robust up-regulation of the lysosomal system. In this study, we investigated alterations of the lysosomal system during different forms of experimental injury in rat hippocampal neurons in culture, utilizing a combination of immunocytochemical and biochemical methods. Using triple-label immnocytochemistry for activated caspase-3, fragmentation of DNA and the microtubule-associated protein-2, we characterized treatment paradigms as models of the apoptotic (staurosporine, camptothecin), the oncotic (high-dose menadione, glutamate), and the mixed apoptotic and oncotic (low-dose menadione) pathways of neuronal death. Slowly developing apoptotic or slowly developing mixed apoptotic and oncotic forms of neuronal injury were associated with substantial increases in the number and size of cathepsin D-positive vesicles (late endosomes and mature lysosomes) as determined by immunocytochemistry, and elevated levels of cathepsin D by western blotting. In agreement with our previous findings in Alzheimer's disease, where lysosomal system activation was not restricted to overtly degenerating neurons, up-regulation of this system was also detected quite early during the course of experimental neuronal injury, preceding the development of dystrophic neurites, nuclear segmentation or fragmentation of DNA. These findings implicate lysosomal system activation, both in Alzheimer's disease and in experimental models of neuronal injury, as an important event associated with early stages of neurodegeneration.
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PMID:Up-regulation of the lysosomal system in experimental models of neuronal injury: implications for Alzheimer's disease. 1109 28

Using an in vitro translation assay to screen a human brain cDNA library, we isolated the microtubule-associated protein Tau and determined it to be a caspase-3 substrate whose C-terminal cleavage occurred during neuronal apoptosis. DeltaTau, the 50-kDa cleavage product, was detected by Western blot in apoptotic cortical cells probed with anti-PHF-1 and anti-Tau-5 antibodies, but not anti-T-46 antibody which recognizes the C-terminus. Overexpression of DeltaTau in SK-N-BE2(C) cells significantly increased the incidence of cell death. Staurosporine-induced Tau cleavage was blocked by 20 microM z-Asp-Glu-Val-Asp-chloromethylketone, a caspase-3 inhibitor, and in vitro, Tau was selectively cleaved by caspase-3 or calpain, a calcium-activated protease, but not by caspases-1, -8, or -9. (D421E)-Tau, a mutant in which Asp421 was replaced with a Glu, was resistant to cleavage by caspase-3 and tended to suppress staurosporine-induced cell death more efficiently than did wild-type Tau in both transient and stable expression systems. Finally, the incidence of DeltaTau-induced cell death was augmented by expression of Abeta precursor protein (APP) or Swedish APP mutant. Taken together, these results suggest that the caspase-3 cleavage product of Tau may contribute to the progression of neuronal cell death in Alzheimer's disease.
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PMID:Proapoptotic effects of tau cleavage product generated by caspase-3. 1116 50

A prominent feature of neurodegenerative diseases is a loss of specific neuronal populations. The pathophysiological mechanisms responsible are, however, poorly understood. Primary cultures of rodent embryonic neurons represent a useful experimental system for investigation of molecular pathways of neurodegeneration and mechanisms of cell death. Here, we report a technique utilizing triple-label immunocytochemistry with confocal immunofluorescence detection designed to simultaneously assess multiple parameters of cell injury in individual hippocampal neurons in primary culture. This method combines detection of DNA damage (TUNEL or Klenow assay) with double-label immunocytochemistry for the activated form of caspase-3 or, alternatively, caspase-cleaved actin (fractin), and microtubule-associated protein-2 (MAP-2) or beta-tubulin. The combined evaluation of the form of nuclear damage (karyorrhexis, pyknosis), the presence or absence of activated caspase-3, and the extent of the damage to cell cytoskeleton, allows for precise assessment of the extent of injury and the mode of cell death (apoptosis, oncosis) for individual neurons.
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PMID:Multiple-label immunocytochemistry for the evaluation of nature of cell death in experimental models of neurodegeneration. 1143 Nov 20

Autophagy is originally named as a process of protein recycling. It begins with sequestering cytoplasmic organelles in a membrane vacuole called autophagosome. Autophagosomes then fuse with lysosomes, where the materials inside are degraded and recycled. To date, however, little is known about the role of autophagy in cancer therapy. In this study, we present that temozolomide (TMZ), a new alkylating agent, inhibited the viability of malignant glioma cells in a dose-dependent manner and induced G2/M arrest. At a clinically achievable dose (100 microM), TMZ induced autophagy, but not apoptosis in malignant glioma cells. After the treatment with TMZ, microtubule-associated protein light-chain 3 (LC3), a mammalian homologue of Apg8p/Aut7p essential for amino-acid starvation-induced autophagy in yeast, was recruited on autophagosome membranes. When autophagy was prevented at an early stage by 3-methyladenine, a phosphatidylinositol 3-phosphate kinase inhibitor, not only the characteristic pattern of LC3 localization, but also the antitumor effect of TMZ was suppressed. On the other hand, bafilomycin A1, a specific inhibitor of vacuolar type H(+)-ATPase, that prevents autophagy at a late stage by inhibiting fusion between autophagosomes and lysosomes, sensitized tumor cells to TMZ by inducing apoptosis through activation of caspase-3 with mitochondrial and lysosomal membrane permeabilization, while LC3 localization pattern stayed the same. These results indicate that TMZ induces autophagy in malignant glioma cells. Application of an autophagy inhibitor that works after the association of LC3 with autophagosome membrane, such as bafilomycin A1, is expected to enhance the cytotoxicity of TMZ for malignant gliomas.
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PMID:Role of autophagy in temozolomide-induced cytotoxicity for malignant glioma cells. 1471 59

Nicotinamide (vitamin B(3)) reduces the infarct volume following focal cerebral ischemia in rats; however, its mechanism of action has not been reported. After cerebral ischemia and/or reperfusion, reactive oxygen species (ROS) and reactive nitrogen species may be generated by inflammatory cells through several cellular pathways, which can lead to intracellular calcium influx and cell damage. Therefore, we investigated the mechanisms of action of nicotinamide in neuroprotection under conditions of hypoxia/reoxygenation. Results showed that nicotinamide significantly protected rat primary cortical cells from hypoxia by reducing lactate dehydrogenase release with 1 h of oxygen-glucose deprivation (OGD) stress. ROS production and calcium influx in neuronal cells during OGD were dose-dependently diminished by up to 10 mM nicotinamide (p < 0.01). This effect was further examined with OGD/reoxygenation (H/R). Cells were stained with the fluorescent dye 4,6-diamidino-2-phenylindole (DAPI) or antibodies against anti-microtubule-associated protein-2 and cleaved caspase-3. Apoptotic cells were studied using Western blotting of cytochrome c and cleaved caspase-3. Results showed that vitamin B(3) reduced cell injury, caspase-3 cleavage and nuclear condensation (DAPI staining) in neuronal cells under H/R. In addition, nicotinamide diminished c-fos and zif268 immediate-early gene expressions following OGD. Taken together, these results indicate that the neuroprotective effect of nicotinamide might occur through these mechanisms in this in vitro ischemia/reperfusion model.
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PMID:Protective effect of nicotinamide on neuronal cells under oxygen and glucose deprivation and hypoxia/reoxygenation. 1515 82

Excessive nitric oxide (NO) production after cerebral hypoxia-ischaemia (HI) may induce cellular injury in various ways, including reaction with superoxide to form the highly reactive peroxynitrite. We characterized the spatial and temporal formation of peroxynitrite through immunohistochemical detection of nitrosylated proteins. Nitrotyrosine immunoreactivity peaked around 3 h post-HI and was detected in areas of injury, as judged by the loss of microtubule-associated protein-2 (MAP-2) staining, in neurones, glia and endothelial cells. Nitrotyrosine staining co-localized with three other cellular markers of injury, active caspase-3, nuclear translocation of apoptosis-inducing factor (AIF) and an oligonucleotide hairpin probe detecting specific DNA strand breaks. The number of nitrotyrosine-positive cells at early time points outnumbered the cells positive for the other three markers of injury, indicating that nitrosylation preceded caspase-3 activation. Pharmacological inhibition of neuronal and inducible nitric oxide synthase (nNOS and iNOS) using 2-iminobiotin, which has been demonstrated earlier to be neuroprotective, significantly reduced nitrotyrosine formation and caspase-3 activation, but not nuclear translocation of AIF, in cortex and striatum of the ipsilatral hemisphere. In summary, nitrotyrosine is an early marker of cellular injury and inhibition of nNOS and iNOS is a promising strategy for neuroprotection after perinatal HI.
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PMID:Nitrosylation precedes caspase-3 activation and translocation of apoptosis-inducing factor in neonatal rat cerebral hypoxia-ischaemia. 1522 2

We attempted to ascertain the neuroprotective effects and mechanisms of minocycline in inflammatory-mediated neurotoxicity using primary neuron/glia co-cultures treated with lipopolysaccharide (LPS). Neuronal cell death was induced by treatment with LPS for 48 h, and the cell damage was assessed using lactate dehydrogenase (LDH) assays and by counting microtubule-associated protein-2 (MAP-2) positive cells. Through terminal transferase deoxyuridine triphosphate-biotin nick end labeling (TUNEL)-staining and by measuring caspase-3 activity, we found that LPS-induced neuronal cell death was mediated by apoptosis. We determined that pre-treatment with minocycline significantly inhibited LPS-induced neuronal cell death. In addition, LPS induced inducible nitric oxide synthase (iNOS) expression significantly, resulting in nitric oxide (NO) production within glial cells, but not in neurons. Both nitric oxide synthase (NOS) inhibitors (N(G)-monomethyl-L-arginine monoacetate (L-NMMA) and S-methylisothiourea sulfate (SMT)) and minocycline inhibited iNOS expression and NO release, and increased neuronal survival in neuron/glia co-cultures. Pre-treatment with minocycline significantly inhibited the rapid and extensive production of tumor necrosis factor-alpha (TNF-alpha) mediated by LPS in glial cells. We also determined that the signaling cascade of LPS-mediated iNOS induction and NO production was mediated by TNF-alpha by using neutralizing antibodies to TNF-alpha. Consequently, our results show that the neuroprotective effect of minocycline is associated with inhibition of iNOS induction and NO production in glial cells, which is mediated by the LPS-induced production of TNF-alpha.
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PMID:Minocycline inhibits apoptotic cell death via attenuation of TNF-alpha expression following iNOS/NO induction by lipopolysaccharide in neuron/glia co-cultures. 1548 88

Insulin-like growth factor I (IGF-I) is a neurotrophic factor that promotes neuronal growth, differentiation and survival. Neuroprotective effects of IGF-I have previously been shown in adult and juvenile rat models of brain injury. We wanted to investigate the neuroprotective effect of IGF-I after hypoxia-ischemia (HI) in 7-day-old neonatal rats and the mechanisms of IGF-I actions in vivo. We also wanted to study effects of HI and/or IGF-I on the serine/threonine kinases Akt and glycogen synthase kinase 3beta (GSK3beta) in the phophatidylinositol-3 kinase (PI3K) pathway. Immediately after HI, phosphorylated Akt (pAkt) and phosphorylated GSK3beta (pGSK3beta) immunoreactivity was lost in the ipsilateral and reduced in the contralateral hemisphere. After 45 min, pAkt levels were restored to control values, whereas pGSK3beta remained low 4 h after HI. Administration of IGF-I (50 microg i.c.v.) after HI resulted in a 40% reduction in brain damage (loss of microtubule-associated protein) compared with vehicle-treated animals. IGF-I treatment without HI was shown to increase pAkt whereas pGSK3beta decreased in the cytosol, but increased in the nuclear fraction. IGF-I treatment after HI increased pAkt in the cytosol and pGSK3beta in both the cytosol and the nuclear fraction in the ipsilateral hemisphere compared with vehicle-treated rats, concomitant with a reduced caspase-3- and caspase-9-like activity. In conclusion, IGF-I induces activation of Akt during recovery after HI which, in combination with inactivation of GSK3beta, may explain the attenuated activation of caspases and reduction of injury in the immature brain.
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PMID:IGF-I neuroprotection in the immature brain after hypoxia-ischemia, involvement of Akt and GSK3beta? 1584 77

Previous studies indicated there is an overall increase of proteolysis in aging rat brains. We monitored the potential degradation of cytoskeletal proteins in neuronal tissue taken from cerebral cortex and cerebellum of young (3 month) and aging (17, 21 and 23.5 month) Wistar rats. We found significant age-dependent proteolysis of cytoskeletal proteins (alphaII-spectrin and microtubule-associated protein MAP-2A/B) in the cerebral cortex and the cerebellum. The pattern of alphaII-spectrin breakdown shows a marked increase in 150- and 145-kDa fragments (SBDP150 and SBDP145, respectively), but we did not detect the caspase-3-mediated 120-kDa fragment (SBDP120) in aged rat brains, suggesting the involvement of the calpain proteases. The pattern of MAP-2A/B breakdown in aged rat brains mirrors that produced by in vitro calpain digestion of 3-month control rat brain MAP-2A/B. In aged rat brains, there is no significant increase in pro-caspase-3 processing; rather, there is a moderate reduction in pro-caspase-3 protein and caspase-3 hydrolytic activity in the cortex. These results point to selective susceptibility of cytoskeletal proteins to calpain-mediated degradation, but not caspase-3 in aging rat brains.
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PMID:Elevation of cytoskeletal protein breakdown in aged Wistar rat brain. 1591 44

Astrin is a microtubule-associated protein and localizes with mitotic spindles in the M-phase. We silenced the expression of astrin protein and tested the cell viability in response to paclitaxel treatment in paclitaxel-sensitive and paclitaxel-resistant cells. We found that the absence of astrin by siRNA resulted in the activation of a p53-dependent apoptosis, which elevated pro-apoptotic Bax expression and increased the activity of caspase-3 in astrin-depleted cells. The HPV18 E6 transcription was found to be inhibited along with the increase expression of p53. Intriguingly, the expression of astrin decreased in paclitaxel-sensitive HeLa cells but remained steady in paclitaxel-resistant cells in response to paclitaxel treatment. Furthermore, we identified that the depletion of astrin caused more cell death both in paclitaxel-sensitive and -resistant cells in combination with paclitaxel treatment. These findings suggest that the silencing of astrin induce a p53-dependent apoptosis and has an additive effect on paclitaxel treatment.
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PMID:Silencing of astrin induces the p53-dependent apoptosis by suppression of HPV18 E6 expression and sensitizes cells to paclitaxel treatment in HeLa cells. 1654 35


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