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Lewy bodies and Lewy neurites are the defining neuropathological characteristics of Parkinson's disease and dementia with Lewy bodies. They are made of abnormal filamentous assemblies of unknown composition. We show here that Lewy bodies and Lewy neurites from Parkinson's disease and dementia with Lewy bodies are stained strongly by antibodies directed against amino-terminal and carboxyl-terminal sequences of alpha-synuclein, showing the presence of full-length or close to full-length alpha-synuclein. The number of alpha-synuclein-stained structures exceeded that immunoreactive for ubiquitin, which is currently the most sensitive marker of Lewy bodies and Lewy neurites. Staining for alpha-synuclein thus will replace staining for ubiquitin as the preferred method for detecting Lewy bodies and Lewy neurites. We have isolated Lewy body filaments by a method used for the extraction of paired helical filaments from Alzheimer's disease brain. By immunoelectron microscopy, extracted filaments were labeled strongly by anti-alpha-synuclein antibodies. The morphologies of the 5- to 10-nm filaments and their staining characteristics suggest that extended alpha-synuclein molecules run parallel to the filament axis and that the filaments are polar structures. These findings indicate that alpha-synuclein forms the major filamentous component of Lewy bodies and Lewy neurites.

Microtubule-associated protein tau is the major constituent of the paired helical filament, the main fibrous component of the neurofibrillary lesions of Alzheimer's disease. Tau is an axonal phosphoprotein in normal adult brain. In Alzheimer's disease brain tau is hyperphosphorylated and is found not only in axons, but also in cell bodies and dendrites of affected nerve cells. We report the production and analysis of transgenic mice that express the longest human brain tau isoform under the control of the human Thy-1 promoter. As in Alzheimer's disease, transgenic human tau protein was present in nerve cell bodies, axons and dendrites; moreover, it was phosphorylated at sites that are hyperphosphorylated in paired helical filaments. We conclude that transgenic human tau protein showed pre-tangle changes similar to those that precede the full neurofibrillary pathology in Alzheimer's disease.

Filamentous inclusions made of alpha-synuclein constitute the defining neuropathological characteristic of Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Rare familial cases of Parkinson's disease are associated with mutations A53T and A30P in alpha-synuclein. We report here the assembly properties and secondary structure characteristics of recombinant alpha-synuclein. Carboxy-terminally truncated human alpha-synuclein (1-87) and (1-120) showed the fastest rates of assembly, followed by human A53T alpha-synuclein, and rat and zebra finch alpha-synuclein. Wild-type human alpha-synuclein and the A30P mutant showed slower rates of assembly. Upon shaking, filaments formed within 48 h at 37 degrees C. The related proteins beta- and gamma-synuclein only assembled after several weeks of incubation. Synthetic human alpha-synuclein filaments were decorated by an antibody directed against the carboxy-terminal 10 amino acids of alpha-synuclein, as were filaments extracted from dementia with Lewy bodies and multiple system atrophy brains. Circular dichroism spectroscopy indicated that alpha-synuclein undergoes a conformational change from random coil to beta-sheet structure during assembly. X-ray diffraction and electron diffraction of the alpha-synuclein assemblies showed a cross-beta conformation characteristic of amyloid.

To facilitate studies of the normal biology of alpha-synuclein, a member of a family of neuronal proteins of unknown function, and to elucidate the role of alpha-synuclein pathologies in neurodegenerative diseases, we generated and characterized a panel of anti-synuclein antibodies. Here we demonstrate that these antibodies recognize defined epitopes spanning the entire length of human alpha-synuclein, and that some of these antibodies also cross-react with zebra finch and rodent synucleins. Since alpha-synuclein has been reported to be a major component of Lewy bodies (LBs) in Parkinson's disease (PD), dementia with LBs and common variants of Alzheimer's disease, we performed immunohistochemical studies showing that these antibodies label numerous LBs in the PD substantia nigra, thereby localizing protein domains throughout human alpha-synuclein in LBs. Taken together, our data indicate that this panel of antibodies can be exploited to probe the normal biology of alpha-synuclein as well as the role of pathological forms of this protein in PD and related neurodegenerative synucleinopathies.

Hyperphosphorylated microtubule-associated protein tau is the major proteinaceous component of the paired helical and straight filaments which constitute a defining neuropathological characteristic of Alzheimer's disease and a number of other neurodegenerative disorders. We have recently shown that full-length recombinant tau assembles into Alzheimer-like filaments upon incubation with heparin. Heparin also promotes phosphorylation of tau by a number of protein kinases, prevents tau from binding to taxol-stabilized microtubules, and produces rapid disassembly of microtubules assembled from tau and tubulin. Here, we have used the above parameters to study the interactions between tau protein and a number of naturally occurring and synthetic glycosaminoglycans. We show that the magnitude of the glycosaminoglycan effects is proportional to their degree of sulfation. Thus, the strongly sulfated glycosaminoglycans dextran sulfate, pentosan polysulfate, and heparin were the most potent, whereas the non-sulfated dextran and hyaluronic acid were without effect. The moderately sulfated glycosaminoglycans heparan sulfate, chondroitin sulfate, and dermatan sulfate had intermediate effects, whereas keratan sulfate had little or no effect. These in vitro interactions between tau protein and sulfated glycosaminoglycans reproduced the known characteristics of paired helical filament-tau from Alzheimer's disease brain. Sulfated glycosaminoglycans are present in nerve cells in Alzheimer's disease brain in the early stages of neurofibrillary degeneration, suggesting that their interactions with tau may constitute a central event in the development of the neuronal pathology of Alzheimer's disease.

PURPOSE This United Kingdom Medical Research Council (UK-MRC) study prospectively evaluated efficacy and long-term toxicity of adjuvant chemotherapy in high-risk stage I nonseminomatous germ cell tumors of the testis (NSGCTT). PATIENTS AND METHODS Eligible patients were those identified by the local histopathologist as having features confirmed in MRC surveillance studies to indicate an approximate 50% risk of relapse. Central histopathology review was undertaken. Chemotherapy consisted of two courses of cisplatin 100 mg/m2, bleomycin 30 mg weekly x 3, and etoposide 120 mg/m2 x 3, every 21 days (BEP). RESULTS One hundred fourteen eligible cases were enrolled. Median time of follow-up was 4 years, with 93 patients followed-up for at least 2 years. There have been two relapses, including one patient who did not have a germ cell tumor (GCT), according to the reference histopathologist. This patient is alive with active disease, the other has died. There was one death after a cerebrovascular accident during treatment. Assessment of fertility, lung function, and audiometry pretreatment and more than 9 months posttreatment indicated no clinically significant changes. A mean decrease in transfer factor coefficient (KCO) of 15% of the predicted value was noted, but no patient had symptomatic respiratory dysfunction. CONCLUSION There have been only two relapses among 114 cases of high-risk stage I NSGCTT treated with two courses of adjuvant BEP chemotherapy. The 95% confidence interval (CI) excludes a true relapse rate of more than 5%. Of 104 patients confirmed on histopathology review to have GCT, there has been only one relapse. Adjuvant chemotherapy is free from significant long-term toxicity, offering an effective alternative to surveillance or retroperitoneal lymph node dissection (RPLND) followed by surveillance, and may be preferred by some patients.

The apolipoprotein E (apoE) type 4 allele (APOE4) is a susceptibility gene for late-onset familial and sporadic Alzheimer disease. ApoE is found in some neurofibrillary tangle-bearing neurons, one of the major pathologic hallmarks of the disease. Neurofibrillary tangles contain paired helical filaments formed from hyperphosphorylated microtubule-associated protein tau. In vitro, tau binds avidly to apoE3, but not to apoE4, forming a bimolecular complex. Tau phosphorylated with a brain extract does not bind either isoform. ApoE3 binds to the microtubule-binding repeat region of tau, which is also the region that is thought to cause self-assembly into the paired helical filament. Binding studies with fragments of ApoE demonstrate that the tau-binding region of apoE3 corresponds to its receptor-binding domain and is distinct from the region that binds lipoprotein particles or beta/A4 peptide. Isoform-specific interactions of apoE with tau may regulate intraneuronal tau metabolism in Alzheimer disease and alter the rate of formation of paired helical filaments and neurofibrillary tangles.

A genetic classification of Alzheimer disease(s) (AD) is presented. We describe a potential metabolic process in individuals who inherit apolipoprotein E-epsilon 4 (APOE4, gene; apoE4, protein) alleles, leading to increased risk and earlier age of onset of late-onset Alzheimer disease. Apolipoprotein E-epsilon 3 (apoE3) binds to tau protein, possibly slowing the initial rate of tau phosphorylation and self-assembly into paired helical filaments (PHFs); apoE4 does not bind tau. Tau promotes microtubule assembly and stabilizes microtubules; hyperphosphorylated tau does not bind, thereby destabilizing microtubules. Hyperphosphorylated tau may self-assemble into PHFs. Over time a bias toward destabilization of microtubules and the formation of neurofibrillary tangles may occur in individuals who inherit APOE4 alleles, leading to a shorter functional neuronal life span. This hypothesis focuses attention on two important aspects of AD research design: (1) Although the inheritance of APOE4 is associated with increased risk and decreased age of onset, apoE4 does not directly cause the disease. Our data point to the absence of an important function of apoE3 or apoE2 in individuals who do not inherit these alleles as the genetically relevant metabolic factor. This has important implications for design of experiments directed toward understanding the relevant neuronal metabolism. (2) Should this hypothesis be proven and confirmed, targets for pharmaceutical therapy designed to mimic the metabolic function of apoE3 or apoE2 become a realistic preventive strategy.

Tau is a neuronal phosphoprotein whose expression is developmentally regulated. A single tau isoform is expressed in fetal human brain but six isoforms are expressed in adult brain, with the fetal isoform corresponding to the shortest of the adult isoforms. Phosphorylation of tau is also developmentally regulated, as fetal tau is phosphorylated at more sites than adult tau. In Alzheimer disease, the six adult tau isoforms become abnormally phosphorylated and form the paired helical filament, the major fibrous component of the characteristic neurofibrillary lesions. We show here that Ser-202 (in the numbering of the longest human brain tau isoform) is a phosphorylation site that distinguishes fetal from adult tau and we identify it as one of the abnormal phosphorylation sites in Alzheimer disease. The abnormal phosphorylation of tau at Ser-202 in Alzheimer disease thus recapitulates normal phosphorylation during development.