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)

Apoptosis, or programmed cell death, is characterized by an active autodestruction of cells. Several proteins inducing (CED-3) or preventing (CED-9) neuronal death have been described in the nematode C. elegans. There is an homology between these proteins and Bcl-2 and ICE (Interleukin-1 beta-Converting Enzyme) in vertebrates. The cascade of biochemical events leading to this active neuronal "suicide" is triggered by initiating factors such as genotoxicity, growth factors deprivation, cytokines (TNF alpha). As the molecular mechanisms of nerve cell death start to be understood, clinicians and neurobiologists are confronted with the difficult problem of pathological aging and neuronal death in patients with neurodegenerative disorders compared to normal aging. In order to distinguish the biochemical abnormalities underlying dysfunction of neurons during aging, neuronal loss during neurodegeneration (Parkinson's disease) and nerve cell death, we searched for morphological and biochemical signs of apoptosis in dopaminergic neurons of the substantia nigra of parkinsonian patients and controls. We found characteristic histopathological features of apoptosis in about 5% of dopaminergic neurons in the brain of patients. In addition, the presence of TNF alpha receptors and the expression of the gene bcl-2 were observed in dopaminergic neurons. Thus, apoptosis could represent the ultimate step of dopaminergic neuronal degeneration in Parkinson's disease. Whether this is also the case in other neurodegenerative diseases still remains to be proven. In brief, neurons in the human brain could be classified into three categories: those which loose slowly part of their functions but are still spared by the process of neuronal death (senescence); those which are lost more rapidly than similar effects due to aging (neurodegeneration); a small number of neurons which die rapidly through apoptosis. The consequences of such observation may be important both for neurobiologists and pharmacologists as the basic mechanisms which result in senescence, disease and death of neurons could be different.
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PMID:[Aging, disease and nerve cell death]. 854 48

Oxidative stress is believed to play important roles in neuronal cell death associated with many different neurodegenerative conditions (e.g., Alzheimer's disease, Parkinson's disease, and cerebral ischemia), and it is believed also that apoptosis is an important mode of cell death in these disorders. Membrane lipid peroxidation has been documented in the brain regions affected in these disorders as well as in cell culture and in vivo models. We now provide evidence that 4-hydroxynonenal (HNE), an aldehydic product of membrane lipid peroxidation, is a key mediator of neuronal apoptosis induced by oxidative stress. HNE induced apoptosis in PC12 cells and primary rat hippocampal neurons. Oxidative insults (FeSO4 and amyloid beta-peptide) induced lipid peroxidation, cellular accumulation of HNE, and apoptosis. Bcl-2 prevented apoptosis of PC12 cells induced by oxidative stress and HNE. Antioxidants that suppress lipid peroxidation protected against apoptosis induced by oxidative insults, but not that induced by HNE. Glutathione, which binds HNE, protected neurons against apoptosis induced by oxidative stress and HNE. PC12 cells expressing Bcl-2 exhibited higher levels of glutathione and lower levels of HNE after oxidative stress. Collectively, the data identify that HNE is a novel nonprotein mediator of oxidative stress-induced neuronal apoptosis and suggest that the antiapoptotic action of glutathione may involve detoxification of HNE.
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PMID:Evidence that 4-hydroxynonenal mediates oxidative stress-induced neuronal apoptosis. 918 46

1. Degeneration of nigrostriatal dopaminergic neurons is the major pathogenic substrate of Parkinson's disease (PD). It is assumed that the lethal trigger is the accumulation of oxidative reactive species generated during metabolism of the natural neurotransmitter dopamine. 2. We have recently shown that dopamine is capable of inducing programmed cell death (PCD) or apoptosis in cultured postmitotic chick sympathetic neurons and rat PC12 pheochromocytoma cells. 3. The bcl-2 gene encodes a protein which blocks physiological PCD in many mammalian cells. In an attempt to elucidate further the mechanism of dopamine toxicity, we examined the potential protective effect of bcl-2 in PC12 cells which were transfected with the protooncogene. 4. In our experiments, Bcl-2 producing cells showed a marked resistance to dopamine toxicity. The percentage of nuclear condensation and DNA fragmentation visualized by the end-labeling method following dopamine treatment was significantly lower in bcl-2 expressing cells. Bcl-2 did not protect PC12 cells against toxicity induced by exposure to dopamine-melanin. Extracts of PC12 cells containing Bcl-2 inhibited dopamine autooxidation and formation of dopamine-melanin. Furthermore, the presence of Bcl-2 protected cells from thiol imbalance and prevented thiol loss following exposure to dopamine. 5. The protective effects of Bcl-2 against dopamine toxicity may be explained, in part, by its action as an antioxidant and by its interference in the production of toxic agents. The possible protection by Bcl-2 against neuronal degeneration caused by dopamine may play a role in the pathogenesis of PD and may provide a new direction for the development of neuroprotective therapies.
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PMID:Dopamine-induced apoptosis is inhibited in PC12 cells expressing Bcl-2. 918 86

Apoptotic, rather than necrotic, nerve cell death now appears as likely to underlie a number of common neurological conditions including stroke, Alzheimer's disease, Parkinson's disease, hereditary retinal dystrophies and Amyotrophic Lateral Sclerosis. Apoptotic neuronal death is a delayed, multistep process and therefore offers a therapeutic opportunity if one or more of these steps can be interrupted or reversed. Research is beginning to show how specific macromolecules play a role in determining the apoptotic death process. We are particularly interested in the critical nature of gradual mitochondrial failure in the apoptotic process and propose that a maintenance of mitochondrial function through the pharmacological modulation of gene expression offers an opportunity for the effective treatment of some types of neurological dysfunction. Our research into the development of small diffusible molecules that reduce apoptosis has grown from studies of the irreversible MAO-B inhibitor (-)-deprenyl. (-)-Deprenyl can reduce neuronal death independently of MAO-B inhibition even after neurons have sustained seemingly lethal damage. (-)-Deprenyl can also influence the process outgrowth of some glial and neuronal populations and can reduce the concentrations of oxidative radicals in damaged cells at concentrations too small to inhibit MAO. In accord with earlier work of others, we showed that (-)-deprenyl alters the expression of a number of mRNAs or of proteins in nerve and glial cells and that the alterations in gene expression/protein synthesis are the result of a selective action on transcription. The alterations in gene expression/protein synthesis are accompanied by a decrease in DNA fragmentation characteristic of apoptosis and the death of responsive cells. The onco-proteins Bcl-2 and Bax and the scavenger proteins Cu/Zn superoxide dismutase (SOD1) and Mn superoxide dismutase (SOD-2) are among the 40-50 proteins whose synthesis is altered by (-)-deprenyl. Since mitochondrial membrane potential correlates with mitochondrial ATP production, we have used confocal laser imaging techniques in living cells to show that the transcriptional changes induced by (-)-deprenyl result in a maintenance of mitochondrial membrane potential, a decrease in intramitochondrial calcium and a decrease in cytoplasmic oxidative radical levels. We therefore propose that (-)-deprenyl acts on gene expression to maintain mitochondrial function and decrease cytoplasmic oxidative radical levels and thereby reduces apoptosis. An understanding of the molecular steps by which (-)-deprenyl selectively alters transcription may lead to the development of new therapies for neurodegenerative diseases.
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PMID:Apoptosis in neurodegenerative disorders: potential for therapy by modifying gene transcription. 926 33

Apoptosis and oxidative stress have been suggested to be involved in Parkinson's disease (PD). However, whether this is a cause or consequence of neurodegeneration is unknown. Incidental Lewy Body disease (ILBD) appears to be a presymptomatic form of Parkinson's disease where individuals are neurologically normal, but after post-mortem examination pathology similar to Parkinson's disease is present. Thus, ILBD can be used to examine the early stages of the pathological process in PD. We investigated the levels of Bcl-2, an anti-apoptotic protein known to decrease cell death induced by several mechanisms, including oxidative stress. Our data show that Bcl-2 is significantly raised in the basal ganglia regions of PD patients as compared to age-matched controls. A similar trend is also found in ILBD. We propose that Bcl-2 increases in some brain regions as an early event and that these brain regions are under a stress for perhaps many years before any symptomatic changes occur.
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PMID:Upregulation of the anti-apoptotic protein Bcl-2 may be an early event in neurodegeneration: studies on Parkinson's and incidental Lewy body disease. 936 87

Double-labelling immunohistochemistry of Bcl-2 and Bax, and ubiquitin (as a marker of Lewy bodies) was examined in the brains of patients with Parkinson's disease and Diffuse Lewy body disease to learn about possible modifications of protein expression and the presence of Lewy bodies. Bcl-2 and Bax immunoreactivities were observed in Lewy body-bearing and non-Lewy body-bearing neurons in patients with parkinsonism. These results show that Bcl-2 and Bax are probably not implicated in Lewy body formation and that the presence of Lewy bodies does not have a direct impact on the expression of Bcl-2 and Bax proteins in individual neurons.
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PMID:Bcl-2 and Bax proteins in Lewy bodies from patients with Parkinson's disease and Diffuse Lewy body disease. 946 59

Manganese is known to induce neurological disorders similar to parkinsonisms. A dopamine deficiency has been demonstrated in Parkinson's disease and in chronic manganese poisoning, suggesting that the mechanisms underlying the neurotoxic effects of the metal ion are related to a functional abnormality of the extrapyramidal system. However, the details have yet to be elucidated. Here we report that manganese causes characteristic internucleosomal DNA fragmentation, a biochemical hallmark of apoptosis, in PC12 cells. It was transcription dependent, relatively specific for manganese, and blocked in Bcl-2-overexpressed PC12 cells. The results indicate that apoptosis may play a role in the dopaminergic neurotoxicity associated with manganese, the first metal to be reported to induce this form of cell death. The early biochemical events show the impairment of energy metabolism, and the process may require new synthesis of proteins such as c-Fos and c-Jun. In addition, manganese induces phosphorylation of c-Jun at Ser63 and Ser73 and SEK1/MKK4 (c-Jun N-terminal kinase kinase) at Thr258 and tyrosine phosphorylation of several proteins. These results indicate that manganese activates specific signal cascades including the c-Jun N-terminal kinase pathway.
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PMID:Activation of JNK pathway and induction of apoptosis by manganese in PC12 cells. 975 Nov 94

Current concepts of the pathogenesis of Parkinson's disease center on the formation of reactive oxygen species (ROS). Dopamine is one of the major sources of ROS. In this study, the molecular events during the dopamine-induced apoptosis in PC-12 cells were studied using auto-oxidized dopamine. Auto-oxidized-dopamine induced DNA fragmentation and activation of c-jun N-terminal kinase (JNK)/stress-activated protein kinase (SAPK) faster and stronger than dopamine. Furthermore, N-acetylcysteine, an antioxidant, prevented the auto-oxidized dopamine-induced JNK/SAPK activation and DNA fragmentation. Meanwhile, Bcl-2 started to decrease after onset of apoptosis, and Bax was increased up to beginning of apoptosis, and thereafter decreased. Therefore, these results suggested that activation of JNK/SAPK and the decreased ratio of antiapoptotic Bcl-2 to proapoptotic Bax appear to be associated with the dopamine-induced apoptosis.
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PMID:Activation of c-jun N-terminal kinase/stress-activated protein kinase and the decreased ratio of Bcl-2 to Bax are associated with the auto-oxidized dopamine-induced apoptosis in PC12 cells. 983 11

6-Hydroxydopamine (6-OHDA) is widely used to selectively lesion dopaminergic neurons of the substantia nigra (SN) in the creation of animal models of Parkinson's disease. In vitro, the death of PC-12 cells caused by exposure to 6-OHDA occurs with characteristics consistent with an apoptotic mechanism of cell death. To test the hypothesis that apoptotic pathways are involved in the death of dopaminergic neurons of the SN caused by 6-OHDA, we created a replication-defective genomic herpes simplex virus-based vector containing the coding sequence for the antiapoptotic peptide Bcl-2 under the transcriptional control of the simian cytomegalovirus immediate early promoter. Transfection of primary cortical neurons in culture with the Bcl-2-producing vector protected those cells from naturally occurring cell death over 3 weeks. Injection of the Bcl-2-expressing vector into SN of rats 1 week before injection of 6-OHDA into the ipsilateral striatum increased the survival of neurons in the SN, detected either by retrograde labeling of those cells with fluorogold or by tyrosine hydroxylase immunocytochemistry, by 50%. These results, demonstrating that death of nigral neurons induced by 6-OHDA lesioning may be blocked by the expression of Bcl-2, are consistent with the notion that cell death in this model system is at least in part apoptotic in nature and suggest that a Bcl-2-expressing vector may have therapeutic potential in the treatment of Parkinson's disease.
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PMID:Herpes simplex virus vector-mediated expression of Bcl-2 prevents 6-hydroxydopamine-induced degeneration of neurons in the substantia nigra in vivo. 1009 66

We studied the substantia nigra of three Parkinson's disease (PD) patients and three age-matched individuals by in situ DNA-end labeling (ISEL) and immunohistochemistry for the apoptosis regulating proteins Bcl-2, Bax and Bcl-x on 50 consecutive sections per patient. No melanin-containing cell was identified with typical apoptotic changes in either patient or control substantia nigra. With prolonged reaction-time the terminal transferase-mediated DNA-end labeling revealed a signal in 2.0 +/-1.2% melanin-containing cells in PD compared to 1.3 +/-1.1% in control. This difference did nor reach statistical significance and no condensation or margination of the chromatin was evident. No significant changes of any of the apoptosis regulating proteins were apparent in PD substantia nigra. These findings do not support the hypothesis that apoptosis plays a central role in the pathogenesis of PD.
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PMID:Cell death and apoptosis regulating proteins in Parkinson's disease--a cautionary note. 1020 82


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