Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0030567 (Parkinson's disease)
 63,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intracellular glutathione (GSH) levels determine whether nitric oxide (NO) is neurotrophic for dopamine neurons or triggers a cell death cascade in primary midbrain cultures. We have investigated herein the role of the extracellular-signal regulated protein kinase (ERK) 1/2 pathway in this GSH switching effect. The short-lived NO donor DEA/NO induces a transient activation of ERK-1/2 that totally disappears 2 h after NO administration. The depletion of GSH increases and the supplementation of GSH suppresses ERK-1/2 activation in response to NO treatment. More interestingly, GSH depletion changes the kinetic of phosphorylation leading to a second prolonged phase of ERK-1/2 activation from 2 to 16 h after NO addition. This change of kinetic is ultimately responsible for NO toxicity under GSH-depleted conditions, because selective blockade of the second and persistent phase of activation prevents cell death. In addition, the only transient ERK activation, induced by NO under normal GSH conditions, did not cause ERK-dependent cell death. Immunocytochemical colocalization studies demonstrate that ERK activation takes place exclusively in glial cells, mainly in astrocytes and less frequently in oligodendrocytes and glial progenitors. Furthermore, glial cell elimination or inactivation in the culture, by gliotoxic drugs, abrogates NO-induced ERK activation. Our results indicate that neurotrophism of NO switches into neurotoxicity after GSH depletion due to persistent activation of the ERK-1/2 signaling pathway in glial cells. The implication of these results in pathological conditions like Parkinson's disease, where GSH depletion and NO overproduction have been documented, are discussed.
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PMID:Selective and persistent activation of extracellular signal-regulated protein kinase by nitric oxide in glial cells induces neuronal degeneration in glutathione-depleted midbrain cultures. 1469 65

Rotenone is a naturally derived pesticide that has recently been shown to evoke the behavioral and pathological symptoms of Parkinson's disease in animal models. Though rotenone is known to be an inhibitor of the mitochondrial complex I electron transport chain, little is known about downstream pathways leading to its toxicity. We used human dopaminergic SH-SY5Y cells to study mechanisms of rotenone-induced neuronal cell death. Our results suggest that rotenone, at nanomolar concentrations, induces apoptosis in SH-SY5Y cells that is caspase-dependent. Furthermore, rotenone treatment induces phosphorylation of c-Jun, the c-Jun N-terminal protein kinase (JNK), and the p38 mitogen activated protein (MAP) kinase, indicative of activation of the p38 and JNK pathways. Importantly, expression of dominant interfering constructs of the JNK or p38 pathways attenuated rotenone-induced apoptosis. These data suggest that rotenone induces apoptosis in the dopaminergic SH-SY5Y cells that requires activation of the JNK and p38 MAP kinases and caspases. These studies provide insights concerning the molecular mechanisms of rotenone-induced apoptosis in neuronal cells.
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PMID:Rotenone-induced apoptosis is mediated by p38 and JNK MAP kinases in human dopaminergic SH-SY5Y cells. 1497 42

The cellular mechanisms underlying the neurodegenerative process in Parkinson's disease are not well understood. Using RNA interference (RNAi), we demonstrate that caspase-3-dependent proteolytic activation of protein kinase Cdelta (PKCdelta) contributes to the degenerative process in dopaminergic neurons. The Parkinsonian toxin MPP(+) activated caspase-3 and proteolytically cleaved PKCdelta into catalytic and regulatory subunits, resulting in persistent kinase activation in mesencephalic dopaminergic neuronal cells. The caspase-3 inhibitor Z-DEVD-FMK and the caspase-9 inhibitor Z-LEHD-FMK effectively blocked MPP(+)-induced PKCdelta proteolytic activation. To characterize the functional role of PKCdelta activation in MPP(+)-induced dopaminergic cell death, RNAi-mediated gene knockdown was performed. Among four siRNAs designed against PKCdelta, two specifically suppressed PKCdelta expression. The application of siRNA abolished the MPP(+)-induced PKCdelta activation, DNA fragmentation, and tyrosine hydroxylase (TH)-positive neuronal loss. Together, these results suggest that proteolytic activation of PKCdelta may be a critical downstream event in the degenerative process of Parkinson's disease.
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PMID:Suppression of caspase-3-dependent proteolytic activation of protein kinase C delta by small interfering RNA prevents MPP+-induced dopaminergic degeneration. 1503 69

We previously demonstrated that the organochlorine pesticide dieldrin, a potential chemical risk factor for development of Parkinson's disease (PD), impairs mitochondrial function and promotes apoptosis in dopaminergic PC12 cells. We further demonstrated that caspase-3-dependent proteolytic activation of a member of the novel PKC family, protein kinase Cdelta (PKCdelta), contributes to apoptotic cell death in dopaminergic cells. In the present study, we report that the proapoptotic function of PKCdelta can be regulated by overexpression of the mitochondrial anti-apoptotic protein Bcl2 in dieldrin-treated dopaminergic cells. Exposure to dieldrin (30 or 100 micro M) for 3 h produced a dose-dependent increase in caspase-3 activation and DNA fragmentation in vector-transfected PC12 cells. Overexpression of human Bcl-2 in PC12 cells completely suppressed dieldrin-induced caspase-3 activation and DNA fragmentation. Furthermore, dieldrin-induced proteolytic activation of PKCdelta was also remarkably reduced in Bcl-2-overexpressed cells. Together, these results suggest that the proapoptotic function of PKCdelta can be regulated by mitochondrial redox modulators during neurodegenerative processes.
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PMID:Proteolytic activation of proapoptotic kinase PKCdelta is regulated by overexpression of Bcl-2: implications for oxidative stress and environmental factors in Parkinson's disease. 1503 12

Oxidative stress is involved in several neurodegenerative diseases including Alzheimer's disease, Parkinson's disease and ischemic reperfusion injury (stroke). We have established clones of the murine hippocampal neuronal cell line HT22, which are resistant to the oxidative stress-causing agents glutamate and hydrogen peroxide, respectively. These cell clones show a mutual cross-resistance to other oxidative stressors, but not to essentially non-oxidative neurotoxins. We have discovered that the amount of phosphorylated, inactive glycogen synthase kinase (GSK) 3beta is elevated in both resistant clones. Pharmacological inhibition of GSK-3beta with lithium chloride in the sensitive parental neuronal cells results in an increased tolerance to glutamate and hydrogen peroxide, suggesting that GSK-3beta is involved in the control of oxidative stress resistance in these cells.
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PMID:Inhibition of glycogen synthase kinase 3 beta is involved in the resistance to oxidative stress in neuronal HT22 cells. 1504 68

Parkinson's disease (PD) is associated with complex compensatory changes in the functional and neurochemical anatomy of the basal ganglia resulting from striatal dopamine deficiency. Available evidence suggests that glutamatergic corticostriatal pathway becomes overactive following nigrostriatal dopaminergic denervation. Since N-methyl-d-aspartate (NMDA) receptors are abundant and functionally important in the striatum, we examined the effects of striatal dopamine deficiency on the distribution and density of NMDA receptor subunit 1 (NR1) and serine phosphorylation (ser897) of NR1 in the striatum. Phosphorylation at this residue is believed to be dependent on protein kinase A. In both 6-hydroxydopamine-lesioned rats and MPTP-treated monkeys, striatal dopamine denervation resulted in down-regulation of NR1 expression and an increase in the expression of ser897-phosphorylated NR1 by striatal neurons. The decreased NR1 expression may be a compensatory response to overactive glutamatergic inputs, which appear to occur in response to striatal dopamine denervation in animal models of PD. Furthermore, the alterations observed in protein kinase A-dependent phosphorylation of NR1 are suggestive of receptor internalization and subcellular trafficking of NR1 in response to increased striatal glutamatergic activity.
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PMID:Differential expression and ser897 phosphorylation of striatal N-methyl-d-aspartate receptor subunit NR1 in animal models of Parkinson's disease. 1508 90

The NMDA receptor complex represents a key molecular element in the pathogenesis of long-term synaptic changes and motor abnormalities in Parkinson's disease (PD). Here we show that NMDA receptor 1 (NR1) subunit and postsynaptic density (PSD)-95 protein levels are selectively reduced in the PSD of dopamine (DA)-denervated striata. These effects are accompanied by an increase in striatal levels of alphaCa2+-calmodulin-dependent protein kinase II (alphaCaMKII) autophosphorylation, along with a higher recruitment of activated alphaCaMKII to the regulatory NMDA receptor NR2A-NR2B subunits. Acute treatment of striatal slices with R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride, but not with l-sulpiride, mimicked the effect of DA denervation on both alphaCaMKII autophosphorylation and corticostriatal synaptic plasticity. In addition to normalizing alphaCaMKII autophosphorylation levels as well as assembly and anchoring of the kinase to the NMDA receptor complex, intrastriatal administration of the CaMKII inhibitors KN-93 (N-[2-[[[3-(4-chlorophenyl)-2-propenyl]methylamino]methyl]phenyl]-N-(2-hydroxyethyl)-4-methoxybenzenesulfonamide) and antennapedia autocamtide-related inhibitory peptide II is able to reverse both the alterations in corticostriatal synaptic plasticity and the deficits in spontaneous motor behavior that are found in an animal model of PD. The same beneficial effects are produced by a regimen of l-3,4-dihydroxyphenylalanine (L-DOPA) treatment, which is able to normalize alphaCaMKII autophosphorylation. These data indicate that abnormal alphaCaMKII autophosphorylation plays a causal role in the alterations of striatal plasticity and motor behavior that follow DA denervation. Normalization of CaMKII activity may be an important underlying mechanism of the therapeutic action of L-DOPA in PD.
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PMID:Abnormal Ca2+-calmodulin-dependent protein kinase II function mediates synaptic and motor deficits in experimental parkinsonism. 1519 99

Mutations in the PINK1 gene (PARK6), a putative serine-threonine kinase, cause autosomal recessive Parkinson's disease. PINK1 functions as a protein kinase and confers protective effects in the mitochondria, where it is primarily located. We assessed in a population of European ancestry whether common genetic variation in this novel gene influences nonmendelian forms of Parkinson's disease. We defined the linkage disequilibrium structure of PINK1 and used this to identify a set of tagging single nucleotide polymorphisms that we estimate will efficiently represent all of the common DNA variation in the entire gene. Genotyping these tags in a set of 576 Parkinson's disease patients and 514 controls did not demonstrate a case-control partition for allele or for haplotype and thus provides evidence against the existence of a common functional variants in PINK1 that has a strong influence on PD risk.
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PMID:The gene responsible for PARK6 Parkinson's disease, PINK1, does not influence common forms of parkinsonism. 1534 59

Wnts are important regulators of dopamine (DA) neuron differentiation in the developing ventral mesencephalon and could thus serve as potential tools in the treatment of Parkinson's disease. In this study, we investigate whether established intracellular Wnt signalling components could modulate the development of DA neurons. Two chemical inhibitors of glycogen synthase kinase (GSK)-3beta, indirubin-3-monoxime and kenpaullone, were found to increase neuronal differentiation in ventral mesencephalon precursor cultures. In addition, the GSK-3beta-specific inhibitor kenpaullone increased the size of the DA neuron population through conversion of precursors expressing the orphan nuclear receptor-related factor 1 into tyrosine hydroxylase positive neurons, thereby mimicking an effect of Wnts. We show that GSK-3beta inhibitors stabilized beta-catenin and that overexpression of beta-catenin in ventral mesencephalic precursors resulted in increased DA differentiation. The three- to fivefold increase in DA differentiation of precursor cells by GSK-3beta inhibitors suggests that such compounds could be used to improve stem/precursor cell therapy approaches in Parkinson's disease.
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PMID:GSK-3beta inhibition/beta-catenin stabilization in ventral midbrain precursors increases differentiation into dopamine neurons. 1552 89

Dopamine (DA) receptor-mediated signal transduction and gene expression play a central role in many brain disorders from schizophrenia to Parkinson's disease to addiction. While trying to evaluate the role of L-type Ca2+ channels in dopamine D1 receptor-mediated phosphorylation of the transcription factor cyclic AMP response element-binding protein (CREB), we found that activation of dopamine D1 receptors alters the properties of L-type Ca2+ channel inhibitors and turns them into facilitators of Ca2+ influx. In D1 receptor-stimulated neurons, L-type Ca2+ channel blockers promote cytosolic Ca2+ accumulation. This leads to the activation of a molecular signal transduction pathway and CREB phosphorylation. In the absence of dopamine receptor stimulation, L-type Ca2+ channel blockers inhibit CREB phosphorylation. The effect of dopamine on L-type Ca2+ channel blockers is dependent on protein kinase A (PKA), suggesting that protein phosphorylation plays a role in this phenomenon. Because of the adverse effect of activated dopamine receptors on L-type Ca2+ channel blocker action, the role of L-type Ca2+ channels in the dopamine D1 receptor signal transduction pathway cannot be assessed with pharmacological tools. However, with antisense technology, we demonstrate that L-type Ca2+ channels contribute to D1 receptor-mediated CREB phosphorylation. We conclude that the D1 receptor signal transduction pathway depends on L-type Ca2+ channels to mediate CREB phosphorylation.
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PMID:L-type Ca2+ channel blockers promote Ca2+ accumulation when dopamine receptors are activated in striatal neurons. 1553 Jun 53


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