Colocalization of tau and alpha-synuclein epitopes in Lewy bodies.
ABSTRACT The major protein constituent of Lewy bodies (LBs), the pathological hallmark of Parkinson disease and dementia with Lewy bodies, is considered to be alpha-synuclein, but other proteins, in particular the microtubule-associated protein tau, have been implicated in the pathogenesis of LBs. Tau is the major structural component of neurofibrillary tangles (NFTs). Both direct immunochemical studies of partially purified LBs and indirect immunohistochemical studies have suggested that LBs may contain tau, but most of these studies were based upon a single tau antibody, and immunologic cross-reactivity was not completely excluded. To gain insight into the relation between tau and alpha-synuclein in LBs, double immunostaining was performed in Lewy body cases with a rabbit polyclonal antibody to alpha-synuclein and a panel of monoclonal antibodies to phospho- and nonphospho-tau epitopes (Alz50, CP9, CP13, PG5, TG3, PHFI) that spanned the length of the tau molecule. Tau-immunoreactive LBs were present in the medulla in 80% of the cases, irrespective of Braak stage. All tau antibodies recognized at least some LBs, arguing against nonspecific antibody cross-reactivity. In most lesions the tau immunostaining was present at the periphery of the LB. The phospho-tau antibody, TG3, detected more LBs than any of the other tau antibodies. The proportion of LBs with tau immunoreactivity was greatest in neurons vulnerable to NETs, such as those in the locus ceruleus and basal nucleus of Meynert, and least in neurons resistant to NFTs, such as the dorsal motor nucleus of the vagus in the medulla. The present results suggest that tau may coaggregate with alpha-synuclein in LBs, especially in neuronal populations vulnerable to both NFTs and LBs.
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ABSTRACT: Using a viral vector for mutant (P301L) tau, we studied the effects of gene transfer to the rat substantia nigra in terms of structural and functional properties of dopaminergic neurons. The mutant tau vector caused progressive loss of pars compacta dopaminergic neurons over time, reduced striatal dopamine content, and amphetamine-stimulated rotational behavior consistent with a specific lesion effect. In addition, structural studies demonstrated neurofibrillary tangles and neuritic pathology. Wild-type tau had similar effects on neuronal loss and rotational behavior. In contrast, mutant alpha-synuclein vectors did not induce rotational behavior, although alpha-synuclein filaments formed in nigrostriatal axons. Dopamine neuron function is affected by tau gene transfer and appears to be more susceptible to tau- rather than alpha-synuclein-related damage in this model. Both tau and alpha-synuclein are important for substantia nigra neurodegeneration models in rats, further indicating their potential as therapeutic targets for human diseases involving loss of dopamine neurons.Neurobiology of Disease 11/2005; 20(1):64-73. DOI:10.1016/j.nbd.2005.02.001 · 5.20 Impact Factor
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ABSTRACT: Recently, a new locus (PARK8) for autosomal dominant parkinsonism has been identified in one large Japanese family. Linkage has been shown to a 16-cM centromeric region of chromosome 12, between markers D12S1631 and D12S339. We tested 21 white families with Parkinson disease and an inheritance pattern compatible with autosomal dominant transmission for linkage in this region. Criteria for inclusion were at least three affected individuals in more than one generation. A total of 29 markers were used to saturate the candidate region. One hundred sixty-seven family members were tested (84 affected and 83 unaffected). Under the assumption of heterogeneity and through use of an affecteds-only model, a maximum multipoint LOD score of 2.01 was achieved in the total sample, with an estimated proportion of families with linkage of 0.32. This LOD score is significant for linkage in a replication study and corresponds to a P value of.0047. Two families (family A [German Canadian] and family D [from western Nebraska]) reached significant linkage on their own, with a combined maximum multipoint LOD score of 3.33, calculated with an affecteds-only model (family A: LOD score 1.67, P=.0028; family D: LOD score 1.67, P=.0028). When a penetrance-dependent model was calculated, the combined multipoint LOD score achieved was 3.92 (family A: LOD score 1.68, P=.0027; family D: LOD score 2.24, P=.0007). On the basis of the multipoint analysis for the combined families A and D, the 1-LOD support interval suggests that the most likely disease location is between a CA repeat polymorphism on genomic clone AC025253 (44.5 Mb) and marker D12S1701 (47.7 Mb). Our data provide evidence that the PARK8 locus is responsible for the disease in a subset of families of white ancestry with autosomal dominant parkinsonism, suggesting that it could be a more common locus.The American Journal of Human Genetics 02/2004; 74(1):11-9. DOI:10.1086/380647 · 10.99 Impact Factor
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ABSTRACT: Multiple system atrophy (MSA) is a sporadic neurodegenerative disease clinically characterized by cerebellar signs, parkinsonism, and autonomic dysfunction. Pathologically, MSA is an α-synucleinopathy affecting striatonigral and olivopontocerebellar systems, while neocortical and limbic involvement is usually minimal. In this study, we describe four patients with atypical MSA with clinical features consistent with frontotemporal dementia (FTD), including two with corticobasal syndrome, one with progressive non-fluent aphasia, and one with behavioral variant FTD. None had autonomic dysfunction. All had frontotemporal atrophy and severe limbic α-synuclein neuronal pathology. The neuronal inclusions were heterogeneous, but included Pick body-like inclusions. The latter were strongly associated with neuronal loss in the hippocampus and amygdala. Unlike typical Pick bodies, the neuronal inclusions were positive on Gallyas silver stain and negative on tau immunohistochemistry. In comparison to 34 typical MSA cases, atypical MSA had significantly more neuronal inclusions in anteromedial temporal lobe and limbic structures. While uncommon, our findings suggest that MSA may present clinically and pathologically as a frontotemporal lobar degeneration (FTLD). We suggest that this may represent a novel subtype of FTLD associated with α-synuclein (FTLD-synuclein).Acta Neuropathologica 05/2015; DOI:10.1007/s00401-015-1442-z · 9.78 Impact Factor