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Query: UNIPROT:P42574 (
caspase-3
)
45,978
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Degeneration of the dopamine (DA) neurons of the substantia nigra pars compacta and the resulting loss of nerve terminals accompanied by DA deficiency in the striatum are responsible for most of the movement disturbances called parkinsonism, observed in Parkinson's disease (PD). One hypothesis of the cause of degeneration of the nigrostriatal DA neurons is that PD is caused by programmed cell death (apoptosis) due to increased levels of cytokines and/or decreased ones of neurotrophins. We and other workers found markedly increased levels of cytokines, such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-2, IL-4, IL-6, transforming growth factor (TFG)-alpha, TGF-beta1, and TGF-beta2, and decreased ones of neurotrophins, such as
brain-derived neurotrophic factor
(
BDNF
) and nerve growth factor (NGF), in the nigrostriatal DA regions and ventricular and lumbar cerebrospinal fluid of PD patients. Furthermore, the levels of TNF-alpha receptor R1 (TNF-R1, p55), bcl-2, soluble Fas (sFas), and the activities of caspase-1 and
caspase-3
were also elevated in the nigrostriatal DA regions in PD. In experimental animal models of PD, IL-1beta level was increased and NGF one decreased in the striatum of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonian mice, and TNF-alpha level was increased in the substantia nigra and striatum of the 6-hydroxydopamine (6OHDA)-injected side of hemiparkinsonian rats. L-DOPA alone or together with 6OHDA does not increase the level of TNF-alpha in the brain in vivo. Increased levels of proinflammatory cytokines, cytokine receptors and caspase activities, and reduced levels of neurotrophins in the nigrostriatal region in PD patients, and in MPTP- and 6OHDA-produced parkinsonian animals suggest increased immune reactivity and programmed cell death (apoptosis) of neuronal and/or glial cells. These data indicate the presence of such proapoptotic environment in the substantia nigra in PD that may induce increased vulnerability of neuronal or glial cells towards a variety of neurotoxic factors. The probable causative linkage among the increased levels of proinflammatory cytokines and the decreased levels of neurotrophins, candidate parkinsonism-producing neurotoxins such as isoquinoline neurotoxins (Review; Nagatsu, 1997), and the genetic susceptibility to toxic factors, remains for further investigation in the molecular mechanism of PD. The increased cytokine levels, decreased neurotrophin ones, and the possible immune response in the nigrostriatal region in PD indicate new neuroprotective therapy including nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, immunosuppressive or immunophilin-binding drugs such as FK-506, and drugs increasing neurotrophins.
...
PMID:Changes in cytokines and neurotrophins in Parkinson's disease. 1120 47
Oxygen-regulated protein 150 kD (ORP150) is a novel endoplasmic-reticulum-associated chaperone induced by hypoxia/ischemia. Although ORP150 was sparingly upregulated in neurons from human brain undergoing ischemic stress, there was robust induction in astrocytes. Cultured neurons overexpressing ORP150 were resistant to hypoxemic stress, whereas astrocytes with inhibited ORP150 expression were more vulnerable. Mice with targeted neuronal overexpression of ORP150 had smaller strokes compared with controls. Neurons with increased ORP150 demonstrated suppressed
caspase-3
-like activity and enhanced
brain-derived neurotrophic factor
(
BDNF
) under hypoxia signaling. These data indicate that ORP150 is an integral participant in ischemic cytoprotective pathways.
...
PMID:ORP150 protects against hypoxia/ischemia-induced neuronal death. 1123 30
Traumatic brain injury (TBI) is a serious neurodisorder commonly caused by car accidents, sports related events or violence. Preventive measures are highly recommended to reduce the risk and number of TBI cases. The primary injury to the brain initiates a secondary injury process that spreads via multiple molecular mechanisms in the pathogenesis of TBI. The events leading to both neurodegeneration and functional recovery after TBI are generalized into four categories: (i) primary injury that disrupts brain tissues; (ii) secondary injury that causes pathophysiology in the brain; (iii) inflammatory response that adds to neurodegeneration; and (iv) repair-regeneration that may contribute to neuronal repair and regeneration to some extent following TBI. Destructive multiple mediators of the secondary injury process ultimately dominate over a few intrinsic protective measures, leading to activation of cysteine proteases such as calpain and
caspase-3
that cleave key cellular substrates and cause cell death. Experimental studies in rodent models of TBI suggest that treatment with calpain inhibitors (e.g., AK295, SJA6017) and neurotrophic factors (e.g., NGF,
BDNF
) can prevent neuronal death and dysfunction in TBI. Currently, there is still no precise therapeutic strategy for the prevention of pathogenesis and neurodegeneration following TBI in humans. The search continues to explore new therapeutic targets and development of promising drugs for the treatment of TBI.
...
PMID:Molecular mechanisms in the pathogenesis of traumatic brain injury. 1237 Nov 42
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.
...
PMID:17beta-estradiol activates ICI 182,780-sensitive estrogen receptors and cyclic GMP-dependent thioredoxin expression for neuroprotection. 1262 28
Lithium has long been one of the primary drugs used to treat bipolar mood disorder. However, neither the etiology of this disease nor the therapeutic mechanism(s) of this drug is well understood. Several lines of clinical evidence suggest that lithium has neurotrophic actions. For example chronic lithium treatment increases the volume of gray matter and the content of N-acetyl-aspartate, a cell survival marker, in bipolar mood disorder patients (Moore et al., 2000). Moreover, treatment with this mood-stabilizer suppresses the decrease in the volume of the subgenual pre-frontal cortex found in bipolar patients (Drevets, 2001). To elucidate molecular mechanisms underlying the neuroprotective and neurotrophic actions of lithium, we employed a preparation of cultured cortical neurons prepared form embryonic rats. We found that treatment with therapeutic doses (0.2-1.2 mM) of lithium robustly protects cortical neurons from multiple insults, notably glutamate-induced excitotoxicity. The neuroprotection against glutamate excitotoxicity is time-dependent, requiring treatment for 5-6 days for maximal effect, and is associated with a reduction in NMDA receptor-mediated Ca2+ influx. The latter is correlated with a decrease in Tyrosine 1472 phosphorylation levels in the NR2B subunit of NMDA receptors and a loss of Src kinase activity which is involved in NR2B tyrosine phosphorylation. Neither the activity of total tyrosine protein kinase nor that of tyrosine protein phosphatase is affected by this drug, indicating the selectivity of the modulation. Lithium neuroprotection against excitotoxicity is inhibited by a
BDNF
-neutralizing antibody and K252a, a Trk antagonist. Lithium treatment time-dependently increases the intracellular level of
BDNF
in cortical neurons and activates its receptor, TrkB. The neuroprotection can be completely blocked by either heterozygous or homozygous knockout of the
BDNF
gene. These results suggest a central role of
BDNF
and TrkB in mediating the neuroprotective effects of this mood-stabilizer. Finally, long-term lithium treatment of cortical neurons stimulates the proliferation of their progenitor cells detected by co-labeling with BrdU and nestin. Lithium pretreatment also blocks the decrease in progenitor proliferation induced by glutamate, glucocorticoids and haloperidol, suggesting a role in CNS neuroplasticity. We used animal models to investigate further therapeutic potentials for lithium. In the MCAO/reperfusion model of stroke, we found that post-insult treatment with lithium robustly reduced infarct volume and neurological deficits. These beneficial effects were evident when therapeutic concentrations of lithium were injected at least up to 3 h after ischemic onset. The neuroprotection was associated with activation of heat-shock factor-1 and induction of heat-shock protein-70, a cytoprotective protein. In a rat excitotoxic model of Huntington's disease, the excitotoxin-induced loss of striatal medium-sized neurons was markedly reduced by lithium. This lithium protection was correlated with up-regulation of cytoprotective Bcl-2 and down-regulation of apoptotic proteins p53 and Bax, and neurons showing DNA damage and
caspase-3
activation. Taken together, our results provide a new insight into the molecular mechanisms involved in lithium neuroprotection against glutamate excitotoxicity. Moreover, these novel molecular and cellular actions might contribute to the neurotrophic and neuroprotective actions of this mood-stabilizer in patients, and could be related to its clinical efficacy for treating mood disorder patients. Clearly, mood-stabilizers may have expanded use for treating excitotoxin-related neurodegenerative diseases.
...
PMID:[Neuroprotective actions of lithium]. 1270 Dec 14
In the serum-free culture of rat embryonic neurons, most neurons rapidly died by necrosis, which was revealed by propidium iodide (PI)-positive staining as early as 3 h after the start of culture and by marked membrane disruption and mitochondrial swelling in transmission electron microscopic (TEM) analysis. However, neither nuclear condensation/fragmentation stained with Hoechst 33342 nor activated
caspase-3
-like immunoreactivity was observed. In the serum-deprived culture, on the other hand, neurons showed apoptotic features, such as
caspase-3
activation and nuclear damages in TEM analysis. Insulin at relatively higher concentrations, up to 100 microg/ml, ameliorated the rapid decrease in survival activity measured with 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt WST-8 assay and PI staining in the serum-free culture, despite the fact that
brain-derived neurotrophic factor
and insulin-like growth factor-I had no survival effect even at concentrations up to 100 microg/ml. Insulin-induced survival effects were abolished by the protein kinase C (PKC) inhibitor calphostin C but not by the phosphatidyl inositol-3-OH-kinase inhibitor wortmannin or the mitogen-activated protein kinase inhibitors PD98059 or U0126. Insulin significantly stimulated the PKC activity in cell lysates and suppressed the mitochondrial swelling and membrane disruption in TEM analysis in a calphostin C-reversible manner. All of these findings suggest that insulin inhibited the neuronal necrosis resistant to known neurotrophic factors under the serum-free culture through PKC mechanisms.
...
PMID:Neuronal necrosis inhibition by insulin through protein kinase C activation. 1280
The human immunodeficiency virus type 1 (HIV-1) envelope protein gp120 has been implicated in the pathogenesis of HIV-1 dementia. Thus, inhibition of gp120 activity could reduce HIV toxicity in the brain. We have used primary cultures of rat cerebellar granule cells to examine mechanisms whereby gp120 causes cell death and to characterize neuroprotective agents. gp120 induced a time- and concentration-dependent apoptotic cell death, which was
caspase-3
-mediated but caspase-1 independent, and was totally blocked by the irreversible
caspase-3
-like protease inhibitor N-acetyl-Asp-Glu-Val-Asp-chloromethylketone.
Caspase-3
activation was observed only in neurons that internalize gp120, indicating that internalization is key to gp120 toxicity. Because
brain-derived neurotrophic factor
(
BDNF
) prevents
caspase-3
-mediated neuronal cell death, we examined whether
BDNF
could prevent gp120-mediated apoptosis. Preincubation of neurons with
BDNF
before the addition of gp120 reduced
caspase-3
activation, and consequently rescued 80% of neurons from apoptosis. Most importantly,
BDNF
reduced the levels of CXC chemokine receptor-4 (CXCR4), a receptor that mediates HIV-1 gp120-induced apoptosis. This effect correlated with the ability of
BDNF
to reduce gp120 internalization and apoptosis. Moreover,
BDNF
blocked the neurotoxic effect of stromal-derived factor-1alpha, a natural ligand for CXCR4, further establishing a correlation between neuroprotection and downregulation of CXCR4. We propose that
BDNF
may be a valid therapy to slow down the progression of HIV/gp120-mediated neurotoxicity.
...
PMID:Brain-derived neurotrophic factor inhibits human immunodeficiency virus-1/gp120-mediated cerebellar granule cell death by preventing gp120 internalization. 1284 75
Huntington's disease (HD) is an autosomal dominant progressive neurodegenerative disorder resulting in selective neuronal loss and dysfunction in the striatum and cortex. The molecular pathways leading to the selectivity of neuronal cell death in HD are poorly understood. Proteolytic processing of full-length mutant huntingtin (Htt) and subsequent events may play an important role in the selective neuronal cell death found in this disease. Despite the identification of Htt as a substrate for caspases, it is not known which caspase(s) cleaves Htt in vivo or whether regional expression of caspases contribute to selective neuronal cells loss. Here, we evaluate whether specific caspases are involved in cell death induced by mutant Htt and if this correlates with our recent finding that Htt is cleaved in vivo at the caspase consensus site 552. We find that caspase-2 cleaves Htt selectively at amino acid 552. Further, Htt recruits caspase-2 into an apoptosome-like complex. Binding of caspase-2 to Htt is polyglutamine repeat-length dependent, and therefore may serve as a critical initiation step in HD cell death. This hypothesis is supported by the requirement of caspase-2 for the death of mouse primary striatal cells derived from HD transgenic mice expressing full-length Htt (YAC72). Expression of catalytically inactive (dominant-negative) forms of caspase-2, caspase-7, and to some extent caspase-6, reduced the cell death of YAC72 primary striatal cells, while the catalytically inactive forms of
caspase-3
, -8, and -9 did not. Histological analysis of post-mortem human brain tissue and YAC72 mice revealed activation of caspases and enhanced caspase-2 immunoreactivity in medium spiny neurons of the striatum and the cortical projection neurons when compared to controls. Further, upregulation of caspase-2 correlates directly with decreased levels of
brain-derived neurotrophic factor
in the cortex and striatum of 3-month YAC72 transgenic mice and therefore suggests that these changes are early events in HD pathogenesis. These data support the involvement of caspase-2 in the selective neuronal cell death associated with HD in the striatum and cortex.
...
PMID:Specific caspase interactions and amplification are involved in selective neuronal vulnerability in Huntington's disease. 1471 58
Functional role(s) for the common neurotrophin receptor p75NTR in nerve growth factor (NGF) signaling have yet to be fully elucidated. Many studies have demonstrated that p75NTR can enhance nerve growth factor-induced survival mediated via the trkA receptor. In addition, newly identified pathways for p75NTR signaling have included distinct p75NTR-specific and trk-independent effects which generally appear to be pro-apoptotic. In the present study, we have examined the influence of p75NTR on NGF-mediated protective effects from hydrogen peroxide (H2O2)-induced apoptotic cell death of PC12 cells. Exposure of PC12 cells to H2O2 resulted in
Caspase-3
activation and apoptosis. NGF protected PC12 cells against H2O2-mediated apoptosis in a dose-dependent manner and inhibited
Caspase-3
activation. These effects of NGF required activation of both PI 3-kinase and MAP kinase signal pathways. When NGF binding to p75NTR was blocked by treating cells with either
BDNF
or PD90780, and where p75NTR expression was reduced by treating cells with antisense oligonucleotide to p75NTR, the protective effects of NGF were attenuated. Further, NGF had no effect on cell viability in PC12nn5 cells, which express only p75NTR. When trk-mediated signal transduction was blocked, leaving p75NTR signaling activated, PC12 cells were not more vulnerable to H2O2. These data suggest that p75NTR enhances the ability of PC12 cells to resist oxidative stress by a trkA-dependent mechanism, potentially by allosteric mechanisms. Further, potential trkA-independent and pro-apoptotic signaling of p75NTR does not contribute to apoptotic cell death of PC12 cells in a setting of oxidative insult.
...
PMID:The common neurotrophin receptor p75NTR enhances the ability of PC12 cells to resist oxidative stress by a trkA-dependent mechanism. 1471 60
The neurotoxicity of conventional antipsychotic drugs has emerged as a potential pathogenic event in extrapyramidal side effects (EPS) and in their limited efficacy for negative-cognitive symptoms in schizophrenic patients. The atypical antipsychotics, recently developed, have superior therapeutic efficacy to treat not only positive symptoms but negative symptoms and cognitive dysfunctions with much lower potentials of side effects, although the influence of atypical antipsychotics on the regulation of neuronal survival has been less investigated. It is important to clarify the effects of typical and atypical antipsychotics on neuronal survival and their contributions to the therapeutic development and understanding of the pathophysiology of schizophrenia. We measured the neurotoxicity of two antipsychotic drug treatments, haloperidol and risperidone, in primary cultured rat cortical neurons. Immunoblotting and pharmacological agent analyses were used to determine the signal transduction changes implicated in the mechanisms of the neurotoxicity. Haloperidol induced apoptotic injury in cultured cortical neurons, but risperidone showed weak potential to injure the neurons. Treatment with haloperidol also led the reduction of phosphorylation levels of Akt, and activated
caspase-3
. The D2 agonist bromocriptine and 5-HT2A antagonist, ketanserin attenuated the haloperidol-induced neuronal toxicity. Moreover,
brain-derived neurotrophic factor
(
BDNF
) reduced the
caspase-3
activity and protected neurons from haloperidol-induced apoptosis.
BDNF
also reversed the reduced levels of phosphorylation of Akt caused by treatment with haloperidol. Haloperidol but not risperidone induces caspase-dependent apoptosis by reducing cellular survival signaling, which possibly contributes to the differential clinical therapeutic efficacy and expression of side effects in schizophrenia.
...
PMID:Neurotoxic potential of haloperidol in comparison with risperidone: implication of Akt-mediated signal changes by haloperidol. 1516 14
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