Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.1.8 (cholinesterase)
12,691 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two novel neuroprotective cholinesterase (ChE) inhibitors, TV3326, (N-propargyl-(3R) aminoindan-5-yl)-ethyl methyl carbamate, and TV3279, (N-propargyl-(3S) aminoindan-5-yl)-ethyl methyl carbamate, were derived from rasagiline for the treatment of Alzheimer's disease (AD). TV3326 also inhibits monoamine oxidase (MAO)-A and -B, whereas its S-isomer, TV3279, lacks MAO inhibitory activity. The action of these drugs in the regulation of amyloid precursor protein (APP) processing, using rat PC12 and human SH-SY5Y neuroblastoma cells, was examined. Both isomers stimulated the release of the non-amyloidogenic a-secretase form of soluble APP (sAPPalpha) from these cell lines. The increases in sAPPalpha, induced by TV3326 and TV3279, were dose-dependent (0.1-100 mM) and blocked by the hydroxamic acid-based metalloprotease inhibitor, Ro31-9790, suggesting mediation via a-secretase activity. Using several signal transduction inhibitors, we identified the involvement of protein kinase C (PKC), mitogen-activated protein (MAP) kinase, and tyrosine kinase-dependent pathways in the enhancement of sAPPalpha release by TV3326 and TV3279. In addition, both drugs directly induced the phosphorylation of p44 and p42 MAP kinase, which was abolished by the specific inhibitors of MAP kinase activation, PD98059 and U0126. These data suggest a novel pharmacological mechanism whereby these ChE inhibitors regulate the secretory processes of APP via activation of the MAP kinase pathway.
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PMID:Involvement of MAP kinase in the regulation of amyloid precursor protein processing by novel cholinesterase inhibitors derived from rasagiline. 1220 96

Deregulation of amyloid precursor protein (APP) processing with increased production of amyloid beta-peptide (Abeta) is considered to be a key pathogenic event in Alzheimer's disease (AD). It has been suggested that stimulation of the muscarinic M(1) receptor subtype affects APP processing and leads to a change in Abeta concentration. To test the hypothesis that treatment with a cholinesterase inhibitor could change the levels of Abeta in plasma, we measured Abeta42 and Abeta40 plasma levels in AD subjects before tacrine treatment and at weeks 2 and 6 of treatment. Treatment with tacrine had no statistically significant effect on plasma Abeta42 and Abeta40 either at 2 weeks or at 6 weeks of administration compared to baseline levels. Plasma Abeta42 and Abeta40 levels showed large subject-to-subject variation but small variation within the same patient over the 3-sample interval. After 2 weeks of treatment with tacrine, there was a strong negative correlation between tacrine concentration and levels of Abeta42 (r = -0.64; p = 0.01) and Abeta40 (r = -0.55; p = 0.04). However, after 6 weeks there was no correlation between plasma concentrations of tacrine and Abeta42 (r = 0.33; p = 0.34) or Abeta40 (r = -0.22; p = 0.54) levels in plasma. After 2 weeks of treatment with an acetylcholinesterase inhibitor, we found a correlation between higher drug concentrations and lower beta-amyloid levels. This might indicate an effect on APP metabolism with an increased alpha-cleavage. But after 6 weeks of drug treatment, there was no obvious drug effect on beta-amyloid concentrations. This finding may indicate that compensatory mechanisms have started at 6 weeks and that no long-term effect on key pathological features in AD is to be expected by an inhibition of acetylcholinesterase.
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PMID:Plasma levels of Abeta42 and Abeta40 in Alzheimer patients during treatment with the acetylcholinesterase inhibitor tacrine. 1221 59

Alzheimer's disease (AD), a progressive, degenerative disorder of the brain, is believed to be the most common cause of dementia amongst the elderly. AD is characterized by the presence of amyloid deposits and neurofibrillary tangles in the brain of afflicted individuals. AD is associated with a loss of the presynaptic markers of the cholinergic system in the brain areas related to memory and learning. AD appears to have a heterogeneous etiology with a large percentage termed sporadic AD arising from unknown causes and a smaller fraction of early onset familial AD (FAD) caused by mutations in one of several genes, such as the beta-amyloid precursor protein (APP) and presenilins (PS1, PS2). These proteins along with tau, secretases, such as beta-amyloid cleaving enzyme (BACE), and apolipoprotein E play important roles in the pathology of AD. On therapeutic fronts, there is significant research underway in the development of new inhibitors for BACE, PS-1 and gamma-secretase as targets for treatment of AD. There is also a remarkable advancement in understanding the function of cholinesterase (ChE) in the brain and the use of ChE-inhibitors in AD. A new generation of acetyl- and butyryl cholinesterase inhibitors is being studied and tested in human clinical trials for AD. The development of vaccination strategies, anti-inflammatory agents, cholesterol-lowering agents, anti-oxidants and hormone therapy are examples of new approaches for treating or slowing the progression of AD. In addition, nutritional, genetic and environmental factors highlight more effective preventive strategies for AD. Developments of early diagnostic tools and of quantitative markers are critical to better follow the course of the disease and to evaluate different therapeutic strategies. In this review, we attempt to critically examine recent trends in AD research from molecular, genetic to clinical areas. We discuss various neurobiological mechanisms that provide the basis of new targets for AD drug development. All these current research efforts should lead to a deeper understanding of the pathobiochemical processes that occur in the AD brain in order to effectively diagnose and prevent their occurrence.
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PMID:A critical analysis of new molecular targets and strategies for drug developments in Alzheimer's disease. 1255 63

Alzheimer's Disease (AD) is a progressive neurodegenerative disorder marked by loss of memory, cognition, and behavioral stability. AD is defined pathologically by extracellular neuritic plaques comprised of fibrillar deposits of beta-amyloid peptide (Abeta) and neurofibrillary tangles comprised of paired helical filaments of hyperphosphorylated tau. Current therapies for AD, such as cholinesterase inhibitors, treat the symptoms but do not modify the progression of the disease. The etiology of AD is unclear. However, data from familial AD mutations (FAD) strongly support the "amyloid cascade hypothesis" of AD, i.e. that neurodegeneration in AD is initiated by the formation of neurotoxic beta-amyloid (Abeta) aggregates; all FAD mutations increase levels of Abeta peptide or density of Abeta deposits. The likely link between Abeta aggregation and AD pathology emphasizes the need for a better understanding of the mechanisms of Abeta production. This review summarizes current therapeutic strategies directed at lowering Abeta levels and decreasing levels of toxic Abeta aggregates through (1) inhibition of the processing of amyloid precursor protein (APP) to Abeta peptide, (2) inhibition, reversal or clearance of Abeta aggregation, (3) cholesterol reduction and (4) Abeta immunization.
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PMID:Emerging beta-amyloid therapies for the treatment of Alzheimer's disease. 1257 Aug 7

Cholinesterase inhibitors improve cognition and behaviour in some patients with Alzheimer's disease (AD). Studies that have focused on methods to predict response to anticholinesterase therapy and markers for response are reviewed. Among the possible predictors of improvement in cognitive outcomes are apolipoprotein genotype, pretreatment postural blood pressure drop, quantitative electroencephalography (qEEG) and disease progression rate. Of these, qEEG profile after a single dose of an acetylcholinesterase inhibitor was consistently found to be a good predictor of cognitive response. Studies have assessed baseline behavioural profiles and baseline single-photon emission computed tomographic profiles as possible predictors of improvement of behavioural symptoms of AD, but these require further study. Possible markers of response during drug treatment include red blood cell cholinesterase inhibition, cerebrospinal fluid monoamine measurement, pupillary response and platelet amyloid precursor protein analyses. Although they, too, require further study, the analysis of platelet amyloid precursor protein may have value as a correlate of the putative disease-modifying effects of long-term treatment. Studying correlates of response may help to elucidate the mechanism of action of acetylcholinesterase inhibitors.
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PMID:Correlates of response to acetylcholinesterase inhibitor therapy in Alzheimer's disease. 1258 47

Alzheimer disease is a complex neurodegenerative dementing illness. It has become a major public health problem because of its increasing prevalence, long duration, high cost of care, and lack of disease-modifying therapy. Over the past few years, however, remarkable advances have taken place in understanding both the genetic and molecular biology associated with the intracellular processing of amyloid and tau and the changes leading to the pathologic formation of extracellular amyloid plaques and the intraneuronal aggregation of hyperphosphorylated tau into neurofibrillary tangles. The identification of disease-causing autosomal dominant mutations as well as gene polymorphisms that alter the risk for pathology indicate that Alzheimer disease is a genetically complex disorder. This progress in our understanding of the molecular pathology has set the stage for clinically meaningful advances in diagnosis and treatment. Emerging diagnostic methods that are based on biochemical and imaging biomarkers of disease-specific pathology hold the potential for accurately diagnosing Alzheimer disease at the earliest stage of the illness--the time when disease-modifying treatment will be most effective. Currently available cholinesterase inhibition therapy targets the cognitive symptoms. However, the goal of new therapies under development is halting the pathologic cascade and potentially reversing the course of the disease. If these new therapies are successful, they will represent a remarkable medical advance for patients and the families who care for them.
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PMID:Alzheimer disease: current concepts and emerging diagnostic and therapeutic strategies. 1470 87

The intensity of interest in therapy for Alzheimer's disease (AD) has accelerated with each passing year. The nature of the effects of cholinesterase inhibitors has been refined with the publication of several studies that have examined long-term therapy as well as different aspects of the symptomatology of AD. Breakthroughs in the basic science of AD has led to new insights into potential therapeutic strategies targeted at the secretases involved in the metabolism of the Alzheimer precursor protein. An immunization approach in which the amyloid-beta protein itself was used as the immunizing agent was discontinued after unexpected toxicity occurred. Other areas of investigation with disappointing results such as estrogen replacement therapy and antiinflammatory approaches are discussed. Several other potential therapeutic agents are also reviewed.
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PMID:Pharmacotherapy for Alzheimer's disease: 2002. 1267 29

Most clinicians and researchers still accept diffuse Lewy body disease (DLBD) as a clinicopathological entity. Dementia with fluctuating cognitive deficits, a parkinsonian syndrome, and visual hallucinations are the core symptoms of this proposed disease entity. From a neuropathological point of view, many examples of patients with progressive dementia showing evidence of extensive Lewy body formation in the cerebral cortex together with the occurrence of Lewy bodies in substantia nigra and locus coeruleus have been identified. Confusingly, a large majority of cases showing typical features of DLBD also present with an Alzheimer pathology in the hippocampus and cerebral cortex. It is far from clear that DLBD represents a specific disease entity rather an intermediate variant between Alzheimer disease and idiopathic parkinsonian syndromes. Nevertheless, from a clinical point of view it may be of importance to characterize patients with a symptomatology of DLBD because important management issues such as avoidance of severe neuroleptic sensitivity reactions, dopaminergic antiparkinsonian treatment and a beneficial response to cholinesterase inhibitors can be applied.
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PMID:Diffuse Lewy body disease - a clinical syndrome or a disease entity? 1276 35

Current approaches to the treatment of cognitive and behavioral symptoms of Alzheimer disease emphasize the use of cholinesterase inhibitors. The kinetic effects of the cholinesterase inhibitors donepezil, galantamine, metrifonate, physostigmine, rivastigmine, and tetrahydroaminoacridine were examined with respect to their action on the esterase and aryl acylamidase activities of human acetylcholinesterase (AChE) and human butyrylcholinesterase (BuChE). Each of these drugs inhibited both AChE and BuChE, but to different degrees. Inhibition of BuChE by these compounds was approximately the same, or better, when acetylthiocholine, the analog of the neurotransmitter acetylcholine, was used as the substrate, instead of butyrylthiocholine. In addition, for these drugs, the inhibition of aryl acylamidase activity paralleled that observed for inhibition of esterase activity of AChE and BuChE. Given that drugs that are currently in use for the treatment of Alzheimer disease inhibit both AChE and BuChE, the development of drugs targeted toward the exclusive inhibition of one or the other cholinesterase may be important for understanding the relative importance of inhibition of BuChE and AChE in the treatment of this disease.
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PMID:Inhibition of human cholinesterases by drugs used to treat Alzheimer disease. 1279 90

Nicotinic receptors (NRs) belong to the group of polymeric receptors of the cell membrane and are key elements of cholinergic transmission. Numerous subtypes of NRs exist with the alpha 4 beta 2 and alpha 7 types being encountered most frequently. Deficiencies in NRs seem to play a role in Alzheimer's disease, which is characterised by accumulation of senile plaques, mainly composed of beta-amyloid peptide (beta A). Although the aetiology of this disease is unknown, different pathogenesis hypotheses implicating alpha 7 NRs have been proposed, with the receptors exerting a direct or indirect action on the mechanism of beta A toxicity. Allosteric modulators of NRs, such as the cholinesterase inhibitor galantamine, that facilitate the action of acetylcholine on these receptors may provide therapeutic benefits in the areas of cognition, attention and antineurodegenerative activity.
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PMID:Nicotinic receptors and Alzheimer's disease. 1281 28


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