Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We searched for the presence of apoptotic cell death and studied the distribution of bcl-2, an oncoprotein that counteracts apoptosis, in amyotrophic lateral sclerosis (ALS). Brain and spinal cord specimens from 12 ALS patients were compared with those from six non-neurological controls. ALS brain tissue was pre-selected by the presence of reactive cortical damage. Apoptosis was demonstrated by in situ end-labelling of fragmented DNA, a method that is suitable for formalin-fixed, paraffin-embedded tissue. All ALS patients exhibited some apoptosis, eight of them did so in each of the three central nervous system (CNS)-levels studied. Apoptosis was not restricted to the motor system, but also affected other neuronal and non-neuronal CNS elements. Apoptosis corresponded with cell shrinkage, and neuronophagia in Nissl stains and with small Nissl-positive bodies. None of the non-neurological controls showed as much apoptosis as any of the ALS cases. Immunocytochemically, the overall distribution of Bcl-2 did not differ between ALS and non-neurological controls. In ALS, however, we found variable degrees of increased Bcl-2 expressed in the nuclei and in the cytoplasm. We found no inverse relationship between apoptosis and bcl-2 expression.
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PMID:Apoptosis in amyotrophic lateral sclerosis is not restricted to motor neurons. Bcl-2 expression is increased in unaffected post-central gyrus. 874 39

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

Animal models of motor neurone disease (MND) are being increasingly used for screening molecules with clinical potential. A number of different treatments to decrease the progression of neuronal cell loss have been proposed; these include: Bcl-2 (B-cell leukaemia oncogene-2), neurotrophic factors, glutamate receptor inhibitors and Ca2+ channel antagonists. In this review Yves Sagot, Richard Vejsada and Ann C. Kato focus on the effects of neurotrophic factors and Bcl-2, both of which have been shown to prevent cell death in various experimental paradigms. Studies performed in animal models of MND have confirmed the potential of these molecules to support motoneurone survival. Some of them have been shown to act in synergy and these results are discussed in the context of molecular mechanisms leading to collaborative and synergistic activities, and also with respect to presumptive subpopulations of motoneurones, which express diverse receptors for neurotrophic factors. Finally, the current status of clinical trials for amyotrophic lateral sclerosis using neurotrophic factors will be discussed, as well as recent reports that neurotrophic factors can exert adverse effects on neuronal survival.
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PMID:Clinical and molecular aspects of motoneurone diseases: animal models, neurotrophic factors and Bcl-2 oncoprotein. 934 52

Mutations in human Cu/Zn superoxide dismutase-1 (SOD) cause approximately 20% of cases of familial amyotrophic lateral sclerosis (FALS). We investigated the mechanism of mutant SOD-induced neuronal degeneration by expressing wild-type and mutant SODs in neuronal cells by means of infection with replication-deficient recombinant adenoviruses. Expression of two FALS-related mutant SODs (A4V and V148G) caused death of differentiated PC12 cells, superior cervical ganglion neurons, and hippocampal pyramidal neurons. Cell death included many features typical of apoptosis. Death could be prevented by copper (Cu2+) chelators, Bcl-2, glutathione, vitamin E, and inhibitors of caspases. Mutant SOD-expressing PC12 cells had higher rates of superoxide (O2-) production under a variety of conditions. The results support the hypothesis that mutant SOD induced-neurodegeneration is associated with disturbances of neuronal free radical homeostasis.
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PMID:Mutant superoxide dismutase-1-linked familial amyotrophic lateral sclerosis: molecular mechanisms of neuronal death and protection. 934 45

In vivo, neuronal over-expression of the anti-apoptotic protein Bcl-2 prevents axotomy-induced motoneuron death and prolongs life in a mouse model of familial amyotrophic lateral sclerosis. The mechanism of these protective effects is still unknown. We have examined, in situ, the influence of Bcl-2 over-expression on the messenger RNA level of two pro-apoptotic, bax and cpp32, and one anti-apoptotic, bcl-xl, regulators of neuronal death. In neonates wild-type mice, cpp32 mRNA was increased in axotomized, dying motoneurons. No changes in bax and bcl-xl messenger RNAs expression were detected. A similar course was observed in protected axotomized neonate motoneurons of transgenic mice over-expressing Bcl-2. In adult wild-type mice no motoneuron death was detected one week after axotomy: bax and cpp32 messenger RNAs were increased and bcl-xl messenger RNA was decreased. Four weeks after the lesion, 60% of the lesioned facial motoneurons had disappeared. In the remaining motoneurons only cpp32 messenger RNA expression was superior to control level. In Bcl-2 transgenic mice, no axotomy-induced facial motoneurons death was detected but the course of the neosynthesis of cell death genes messenger RNAs was similar to wild-type mice. Bax, Bcl-x and CPP32 immunoreactivity were increased in facial motoneurons after axotomy. Thus, fatal axotomy induces cell death genes bax and cpp32 messenger RNAs neosynthesis which is not prevented by athanatal Bcl-2 over-expression. This suggests that the protective effect of Bcl-2 results from interactions with Bax and CPP32 at the post-translation level without repercussion at the messenger RNA level. Axotomy induces cell death messenger RNA neosynthesis potentially harmful at long-term despite Bcl-2 over-expression.
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PMID:cpp32 messenger RNA neosynthesis is induced by fatal axotomy and is not regulated by athanatal Bcl-2 over-expression. 1021 67

The mechanisms for neurodegeneration in amyotrophic lateral sclerosis (ALS) are not understood. We found that motor neuron degeneration in ALS structurally resembles apoptosis. The progression of neuronal death is divisible into 3 sequential stages: chromatolysis, somatodendritic attrition, and apoptosis. In ALS spinal cord anterior horn and motor cortex, DNA fragmentation is detectable in situ and in gels and is internucleosomal, occurring in the presence of DNA fragmentation factor-45/40 activation and increased caspase-3 activity. By immunoblotting, changes occur in the subcellular distribution of cell death proteins that would promote apoptosis. In selectively vulnerable CNS regions in ALS compared with controls, the proapoptotic proteins Bax and Bak are elevated in the mitochondrial-enriched membrane compartment, but are reduced or unchanged in the cytosol. In contrast, the antiapoptotic protein Bcl-2 is decreased in the mitochondrial-enriched membrane compartment of vulnerable regions in ALS, but is increased in the cytosol, whereas Bcl-xL levels are unchanged in both subcellular compartments. Coimmunoprecipitation experiments showed that Bax-Bax interactions are greater in the mitochondrial-enriched membrane compartment of ALS motor cortex compared with controls, whereas Bax-Bcl-2 interactions are lower in the membrane compartment of ALS motor cortex compared with controls. We conclude that a PCD mechanism, involving cytosol-to-membrane and membrane-to-cytosol redistribution of cell death proteins and caspase-3 activation, participates in the pathogenesis of ALS.
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PMID:Neuronal death in amyotrophic lateral sclerosis is apoptosis: possible contribution of a programmed cell death mechanism. 1033 34

Transgenic mice with a point mutation in the light neurofilament gene develop amyotrophic lateral sclerosis-like motor neuron disease characterized by selective spinal motor neuron loss, neurofilamentous accumulations, and severe muscle atrophy. To test whether the large motor neurons at risk in this disease could be protected from mutant neurofilament-mediated killing, these mice were bred to mice overexpressing the human Bcl-2 proto-oncogene. Elevated levels of Bcl-2 increased the numbers of motor and sensory axons surviving after the developmental period of naturally occurring cell death but did not greatly reduce the number of degenerating axons or protect the large motor neurons from mutant neurofilament-mediated death.
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PMID:Bcl-2 overexpression does not protect neurons from mutant neurofilament-mediated motor neuron degeneration. 1041 73

It has been proposed that mutations in copper/zinc-superoxide dismutase (SOD1), the only proven cause of amyotrophic lateral sclerosis (ALS), induce the disease by a toxic property that promotes apoptosis. Consistent with this, we have demonstrated that overexpression of Bcl-2, a protein that inhibits apoptosis, attenuates neurodegeneration produced by the familial ALS-linked SOD1 mutant G93A (mSOD1). Herein, we assessed the status of key members of the Bcl-2 family in the spinal cord of transgenic mSOD1 mice at different stages of the disease. In asymptomatic transgenic mSOD1 mice, expression of Bcl-2, Bcl-XL, Bad, and Bax does not differ from that in nontransgenic mice. In contrast, in symptomatic mice, expression of Bcl-2 and Bcl-XL, which inhibit apoptosis, is reduced, whereas expression of Bad and Bax, which stimulate apoptosis, is increased. These alterations are specific to affected brain regions and are caused by the mutant and not by the normal SOD1 enzyme. Relevant to the neuroprotective effects of Bcl-2 in transgenic mSOD1 mice, overexpression of Bcl-2 increases the formation of Bcl-2:Bax heterodimers, which abolish the Bax proapoptotic property. This study demonstrates significant alterations in the expression of key members of the Bcl-2 family associated with mSOD1 deleterious effects. That these changes contribute to the neurodegenerative process in this model of ALS is supported by our observations in double transgenic mSOD1/Bcl-2 mice in which the pernicious increase of Bax is tempered by an increase in formation of Bcl-2:Bax heterodimers. Based on these findings, it may be concluded that Bcl-2 family members appear as invaluable targets for the development of new neuroprotective therapies in ALS.
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PMID:Bax and Bcl-2 interaction in a transgenic mouse model of familial amyotrophic lateral sclerosis. 1058 6

Prostate apoptosis response-4 (Par-4) is a 38-kDa protein initially identified as the product of a gene upregulated in prostate tumor cells undergoing apoptosis. Par-4 contains both a death domain and a leucine zipper domain, and has been shown to interact with several proteins known to modulate apoptosis, including protein kinase Czeta, Bcl-2, and caspase-8. A rapid increase in Par-4 levels occurs in neurons undergoing apoptosis in a variety of paradigms, including trophic factor withdrawal, and exposure to oxidative and metabolic insults. Par-4, which can be induced at the translational level, acts at an early stage of the apoptotic cascade prior to caspase activation and mitochondrial dysfunction. The mechanism whereby Par-4 promotes apoptosis may involve inhibition of the antiapoptotic transcription factor NF-kappaB and suppression of Bcl-2 expression and/or function. Studies of postmortem tissues from patients and animal models of neurodegenerative disorders, including Alzheimer's, Parkinson's, and Huntington's diseases, amyotrophic lateral sclerosis (ALS), and HIV encephalitis, have documented increased levels of Par-4 in vulnerable neurons. Manipulations that block Par-4 expression or function prevent neuronal cell death in models of each disorder, suggesting a critical role for Par-4 in the neurodegenerative process. Interestingly, Par-4 levels rapidly increase in synaptic terminals following various insults, and such local increases in Par-4 levels appear to play important roles in synaptic dysfunction and degeneration. A better understanding of the molecular and cellular biology of Par-4 will help clarify mechanisms of neuronal apoptosis, and may lead to the development of novel preventative and therapeutic strategies for neurodegenerative disorders.
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PMID:Par-4: an emerging pivotal player in neuronal apoptosis and neurodegenerative disorders. 1069 Dec 89

The most frequent genetic causes of amyotrophic lateral sclerosis (ALS) determined so far are mutations occurring in the gene for copper/zinc superoxide dismutase (CuZnSOD). The mechanism may involve inappropriate formation of hyroxyl radicals, peroxynitrite or malfunctioning of the SOD protein. We hypothesized that undiscovered genetic causes of sporadically occurring amyotrophic lateral sclerosis might be found in the mechanisms that create and destroy oxygen free radicals within the cell. After determining that there were no CuZnSOD mutations present, we measured superoxide production from mitochondria and manganese superoxide dismutase (MnSOD), glutathione peroxidase, NFkappaB, Bcl-2 and Bax by immunoblot. Of the ten sporadic patients we tested we found three patients with significantly increased concentrations of MnSOD. These patients also had lower levels of superoxide production from mitochondria and decreased expression of Bcl-2. No mutations were found in the cDNA sequence of either MnSOD in any of the sporadic patients. A patient with a CuZnSOD mutation (G82R) used as a positive control showed none of these abnormalities. The patients displaying the MnSOD aberrations showed no specific distinguishing features. This result suggests that the cause of ALS in a subgroup of ALS patients (30%) is genetic in origin and can be identified by these markers. The alteration in MnSOD and Bcl-2 are likely epiphenomena resulting from the primary genetic defect. It suggests also that the oxygen free radicals are part of the cause in this subgroup and that dysregulation of MnSOD or increased endogenous superoxide production might be responsible.
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PMID:Manganese superoxide dismutase levels are elevated in a proportion of amyotrophic lateral sclerosis patient cell lines. 1087 11


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