Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10636 (tau protein)
 5,110 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tauopathy is defined as abnormal accumulation of aberrantly phosphorylated microtubule-associated protein tau in the central nervous system, best demonstrated by immunocytochemistry using anti-tau antibodies. The newly recognized familial tauopathy with mutation in tau gene, that is located on chromosome 17, confirms that the process directly leads to neuronal degeneration. Tau consists of six isoforms translated from alternative splicing of a single gene. They are classified into three repeat (3R) and four repeat (4R) subtypes, by the number of microtubulus-binding domain from the reading or skipping of the exon 10. In sporadic tauopathy, 3R + 4R accumulate in Alzehimer's disease (AD), 3R in Pick's disease, and 4R in progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). In familial tauopathy, the mutations affecting the splicing of the exon 10 accumulate 4R and phenotypically mimick CBD/PSP, while majority of others simulate neurofibrillary tangle-predominant form of dementia (NFTD). Argyrophlic grains (AG) are tau-immunoreactive comma-shaped or filiform structure, and argyrophilic grain dementia (AGD) is a form of senile dementia carrying AG as only morphological substrate explaining dementia. In our consecutive autopsy cases from the oldest old, AGD is the second leading cause of degenerative type of dementia, highlighting the importance of tauopathy in the aging and dementia.
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PMID:[Dynamic neuropathology of tauopathy]. 1223 8

MAPT, the gene encoding tau, was screened for mutations in 96 progressive supranuclear palsy subjects. A point mutation (R5L) was identified in a single progressive supranuclear palsy subject that was not in the other progressive supranuclear palsy subjects or in 96 controls. Functionally, this mutation alters the ability of tau to promote microtubule assembly. Analysis of soluble tau from different brain regions indicates that the mutation does not affect the ratio of tau isoforms synthesized. Aggregated insoluble tau from subcortical regions was predominantly four-repeat tau with no or one amino terminal insert (0N4R and 1N4R). Insoluble tau from cortical regions also contained 1N3R tau. Thus, the R5L mutation causes a progressive supranuclear palsy phenotype, presumably by a gain-of-function mechanism.
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PMID:An R5L tau mutation in a subject with a progressive supranuclear palsy phenotype. 1232 83

Pathological alterations in the microtubule-associated protein (MAP) tau are well-established in a number of neurodegenerative disorders, including Alzheimer's Disease (AD), frontotemporal dementia (FTD), progressive supranuclear palsy (PSP), and others. Tau protein and in some cases, neurofilament subunits exhibit abnormal phosphorylation on specific serine and threonine residues in these diseases. A large body of biochemical, genetic, and cell biological evidence implicate two major serine-threonine protein kinases, glycogen synthase kinase 3 (GSK-3) and cyclin-dependent kinase 5 (CDK5) as major kinases responsible for both normal and pathological phosphorylation of tau protein in vivo. What remains unclear is whether tau phosphorylation and/or neurofibrillary tangle (NFT) formation are causal or secondary to initiation of neuronal pathology. In fact, many studies have indicated that tau misphosphorylation is not the causal event. Interestingly, some of these kinase and phosphatase activities have recently merged as key regulators of fast axonal transport (FAT). Specifically, CDK5 and GSK-3 have been recently shown to regulate kinesin-driven motility. Given the essential role of FAT in neuronal function, an alternate model for pathogenesis can be proposed. In this model, misregulation of FAT induced by an imbalance in specific kinase-phosphatase activities within neurons represents an early and critical step for the initiation of neuronal pathology. Such a model may explain many of the unique characteristics of late onset of neurological diseases such as AD.
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PMID:Fast axonal transport misregulation and Alzheimer's disease. 1242 5

Oxidative stress phenomena have been related with the onset of neurodegenerative diseases. Particularly in Alzheimer Disease (AD), oxygen reactive species (ROS) and its derivatives can be found in brain samples of postmortem AD patients. However, the mechanisms by which oxygen reactive species can alter neuronal function are still not elucidated. There is a growing amount of evidence pointing to a role for mitochondrial damage as the source of free radicals involved in oxidative stress. Among the species that participate in the production of oxygen reactive radicals, transition metals are one of the most important. Several reports have implicated the involvement of redox-active metals with the onset of different neurodegenerative diseases such as Alzheimer's Disease (AD), Progressive Supranuclear Palsy (PSP), Amyotrophic Lateral Sclerosis (ALS) and Parkinson's Disease (PD). On the other hand, our previous studies have indicated that A beta-induced deregulation of the protein kinase Cdk5 associated with tau protein hyperphosphorylation constitute a critical pathway toward neurodegeneration. In the current paper we have shown that iron induces an imbalance in the function of Cdk5/p25 system of hippocampal neurons, resulting in a marked decrease in tau phosphorylation at the typical Alzheimer's epitopes. The loss of phosphorylated tau epitopes correlated with an increase in 4-hydroxy-nonenal (HNE) adducts revealing damage by oxidative stress. This effects on tau phosphorylation patterns seems to be a consequence of a decrease in the Cdk5/p25 complex activity that appears to result from a depletion of the activator p25, a mechanism in which calcium transients could be implicated.
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PMID:Iron-induced oxidative stress modify tau phosphorylation patterns in hippocampal cell cultures. 1257 81

Tau phosphorylation was examined in argyrophilic grain disease (AGD) by using the phosphospecific tau antibodies Thr181, Ser202, Ser214, Ser 396 and Ser422, and antibodies to non-phosphorylated and phosphorylated mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinases (ERK), stress-activated kinase (SAPK), c-Jun N-terminal kinase (JNK), p38 kinase (p-38), alpha-calcium/calmodulin-dependent kinase II (alphaCaM kinase II), and glycogen synthase kinase-3 (GSK-3), all of which regulate phosphorylation at specific sites of tau. This is the first study in which the role of protein kinases in tau phosphorylation has been examined in AGD. Hyperphosphorylated tau accumulated in grains and pre-tangles in the hippocampus, dentate gyrus, entorhinal and trans-entorhinal cortices, and amygdala in all cases. Ballooned neurons in the amygdala, entorhinal, insular and cingulate cortex, and claustrum contained alphaB-crystallyn and phosphorylated neurofilament epitopes. Some astrocytes and scattered oligodendrocytes containing coiled bodies were recognized with anti-tau antibodies. A few tangles were observed in the entorhinal cortex and hippocampus corresponding to Alzheimer's disease (AD) stages I-III of Braak and Braak. None of the present cases was associated with progressive supranuclear palsy or with alpha-synuclein pathology. Two bands of phospho-tau of 64 and 68 kDa were observed in Western blots of sarkosyl-insoluble fractions enriched with abnormal filaments in AGD, a pattern that contrasts with the 4-band pattern obtained in AD. No modifications in the expression of non-phosphorylated MEK-1, ERK2 and GSK-3alpha/beta, as revealed by immunohistochemistry, were seen in AGD, but sarkosyl-insoluble fractions were particularly enriched in JNK-1 and alphaCaM kinase II. Increased expression of the phosphorylated (P) forms of MAPK/ERK, SAPK/JNK, p38 and GSK-3beta was found in grains and tau-containing cells in AGD. MAPK/ERK-P immunoreactivity was observed in pre-tangles and, diffusely, in the cytoplasm of ballooned neurons, but not in grains. Strong SAPK/JNK-P and P38-P, and moderate GSK-3b-P immunoreactivities selectively occured in grains, in neurons with pre-tangles and in the peripheral region of the cytoplasm of ballooned neurons. MAPK/ERK-P, SAPK/JNK-P, p38-P and GSK-3beta-P were expressed in tau-containing astrocytes and in oligodendrocytes with coiled bodies. Western blots revealed kinase expression in sarkosyl-insoluble fractions but none of the phospho-kinase antibodies recognized hyper-phosphorylated tau protein. These findings indicate complex, specific profiles of tau phosphorylation and concomitant activation of precise kinases that have the capacity to phosphorylate tau at specific sites in AGD. These kinases co-localize abnormal tau in selected structures and cells, including neurons with pre-tangles, ballooned neurons, astrocytes and oligodendrocytes. Most of these kinases are involved in cell death and cell survival in certain experimental paradigms. However, double-labeling studies with the method of in situ end-labeling of nuclear DNA fragmentation and cleaved (active) caspase-3 immunohistochemistry show no expression of apoptosis and death markers in cells bearing phosphorylated kinases.
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PMID:Phosphorylated protein kinases associated with neuronal and glial tau deposits in argyrophilic grain disease. 1258 May 46

The microtubule-associated protein tau accumulates as cytoplasmic inclusions in Alzheimer's disease (AD), Pick's disease (PiD), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). We investigated the immunoreactivity of tau-positive structures using a panel of antibodies to epitopes spanning the entire length of the tau molecule. In ethanol-fixed brain tissues, most antibodies to the microtubule-binding domain (MBD) required formic acid (FA) treatment to stain tau inclusions in PSP and CBD. This is in contrast with the intense labeling of neurofibrillary tangles in AD without FA treatment. Pick bodies (PiB) in PiD showed an intermediate pattern with respect to the immunoreactivity of the MBD because accumulated tau in PiB mostly lacks the insertion of exon 10, and the proportion of tau phosphorylated at Ser262 is smaller than in other abnormal tau structures. Such immunohistochemical profiles appeared to correlate with the occurrence of the smeared tau on immunoblot analysis of brain homogenate. The smeared tau was more abundant in AD and PiD than in PSP and CBD. Since the smeared tau was N-terminally truncated and was characteristic of advanced forms of modified tau, these findings suggest that tau accumulated in AD and PiD was processed more markedly than that in PSP and CBD. The MBD of tau may be masked in the presence of the intact N terminus and require FA treatment for antibody recognition in tissue sections. Advanced modification may expose the MBD in brain tissues of AD and PiD. It is suggested that the processing of abnormally accumulated tau characterizes the pathophysiology of each tauopathy.
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PMID:Different immunoreactivities of the microtubule-binding region of tau and its molecular basis in brains from patients with Alzheimer's disease, Pick's disease, progressive supranuclear palsy and corticobasal degeneration. 1267 50

The diffuse nature of the lesions in neurodegenerative parkinsonian syndromes explains the inefficacy of symptomatic treatments and the potential interest of neuroprotector treatments that could slow down or even prevent neuron degeneration in structures involved in the degenerative processes. As these syndromes share preferential degeneration of the substantia nigra with Parkinson's disease it is logical to hypothesize that the same mechanisms of neuron death are involved. The responsibility of an exotoxin, with a mechanism of action that would be similar to that of MPTP and/or rotenone, appears to be implicated only in progressive supranuclear palsy (PSP): this is suggested by the "guadeloupean parkinsonean" syndrome. There is no evidence demonstrating an exotoxin in corticobasal degeneration (CBD), which might play an anecdotal role in rare cases of multiple system atrophy (MSA). There are rare cases of PSP, sometimes with autopsy proof, generally with autosomal dominant inheritance, but in the much larger number of sporadic cases there is an undeniable genetic susceptibility linked with certain polymorphisms of the tau protein gene. Genetic susceptibility plays a much less pronounced role in CBD. There is no argument however in favor of a genetic factor in MSA. A few arguments suggest that oxidative stress is involved in PSP and MSA, or even CBD, but no evidence of a primary effect. Perturbed mitochondrial metabolism is possible in PSP. Undeniable proof of the effect of inflammation, excitotoxicity, and apoptosis remains to be presented. We now have several compounds which could affect different phases of neurodegeneration. Identifying the precise cause of neuronal death is needed to properly choose the most effective therapeutic approach (single drug or multiple drug regimens). Therapeutic assessment should be conducted in patients with certain diagnosis. This apparently evident prerequisite does not however appear to be easy to satisfy as has been demonstrated by anatomoclinical series in PSP and MSA, and even more so in CBD. Use of international criteria does not alleviate the difficulty. Satisfactory criteria of efficacy remain to be identified. Assuming that such trials would be conclusive, there remains the question of how to implement neuroprotection in routine practice. The difficulties encountered are well known: late intervention after development of the disease in sporadic cases, ethical issues concerning preclinical screening in familial forms of the disease or in patients exposed to an exotoxin.
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PMID:[Neuroprotection and neurodegenerative parkinsonian syndromes]. 1277 94

The Hohara village of the Kii peninsula is one of the high incidence ALS foci, and the high incidence was reported to have ended in early 1980s. However, we have found the ALS incidence rate has been still high, more than 100 times of the other areas of Japan. In addition, we have found many cases of parkinsonism-dementia complex (PDC). ALS and PDC often occur simultaneously in a single patient or in a single family. Family history was positive in more than 70% of patients. ALS and PDC showed common neuropathological findings consisting of ALS pathology and many neurofibrillary tangles (NFT) without senile plagues, and isoform pattern of NFT tau protein was similar to that of Alzheimer disease (AD), but different from that of progressive supranuclear palsy (PSP) or Pick's disease (PiD). Kii ALS/PDC may be a novel tauopathy that differ from AD, PSP or PiD.
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PMID:[Amyotrophic lateral sclerosis-parkinsonism-dementia complex of the Kii Peninsula of Japan]. 1278 69

The diagnostic significance of tau proteins in cerebrospinal fluids (CSF) has been described in many cases of dementia of Alzheimer type (AD). However, in patients with other diseases showing neurofibrillary tangles (NFT) similar to those in AD, tau proteins in cerebrospinal fluids have not been rigorously investigated. In particular, differentiating corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP) is clinically and pathologically difficult, and a useful biochemical marker to discriminate these two diseases has been a subjects of clinical interest. Therefore, we examined the usefulness of CSF tau and amyloid beta (A beta) proteins for the differentiation between CBD and PSP. CSF total tau (t-tau) and A beta proteins were measured with the sandwich ELISA method (Innogenetics, Belgium). CSF tau protein phosphorylated at serine 199 (p-tau) was measured by a recent established sandwich ELISA (Mitsubishi Chemical Co.). In conclusion, measurement of tau protein levels in CSF may be useful for the differential diagnosis of CBD from PSP. We also suggest that CSF p-tau may be a better biochemical marker than CSF t-tau.
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PMID:[Corticobasal degeneration and progressive supranuclear palsy--biochemical marker]. 1278 94

Pathological inclusions containing fibrillar aggregates of hyperphosphorylated tau protein are a characteristic feature in the tauopathies, which include Alzheimer's disease, frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17), progressive supranuclear palsy, corticobasal degeneration and Pick's disease. Tau isoform composition and cellular and regional distribution as well as morphology of these inclusions vary in each disorder. Recently, several pathological missense and exon 10 splice-donor site mutations of the tau gene were identified in FTDP-17. Exon 10 codes for the second of four microtubule-binding repeat domains. The splice-site mutations result in increased inclusion of exon 10 which causes a relative increase in tau isoforms containing four microtubule-binding repeat domains over those containing three repeat domains. This could be a central aetiological mechanism in FTDP-17 and, perhaps, other related tauopathies. We have investigated changes in the ratio and distribution of three-repeat and four-repeat tau in the different tauopathies as a basis of the phenotypic range of these disorders and the selective vulnerability of different subsets of neurones. In this study, we have developed two monoclonal antibodies, RD3 and RD4 that effectively distinguish these closely related tau isoforms. These new isoform-specific antibodies are useful tools for analysing tau isoform expression and distribution as well as pathological changes in the human brain.
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PMID:Pathological inclusion bodies in tauopathies contain distinct complements of tau with three or four microtubule-binding repeat domains as demonstrated by new specific monoclonal antibodies. 1278 26


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